turkey says it will retaliate after a car bomb kills at least 28 military personnel in ankara the world news from jalalabads. also ahead-- al jazeera. polls open in uganda when the prime minister seeks to extend his 30 year rule. a petrol rush to save the

committeement a pope heconomy. and more on the pope turkey's president says a bombing in the acapital will only strengthen the country's resolve. retaliation is promised saying the fight will go on against what it called pawns that carry out such attacks. 28 people were killed by a car bomb used against military buses. our correspondent reports. >> reporter: the heart of turkey's capital dropped by a massive explosion in only four months after the last deadly bomb attack in this city. the governor of ankara says the bomb caused by a car bottom. the convoy was close to the military headquarters in the capital as well as the

parliament. security officials have said that the initial signs indicate the outlawd kurdistan workers party or p.k.k. is behind the attack. >> translation: the purpose of this attack is to intimidate our country and to inflict fear into our citizens' mind. we all should be united because the terrorists are aiming to divide us >> reporter: it has not been an isolated incident. in the past few months there have been four deadly bombings in turkey. one bomber blew himself up in istanbul in january. ten died in the attack. the bomber was believed to have been inspired by islamic state in iraq and the levant. last october two bombs exploded outside of the railway astation. more than 1000 were killed in

those blasts. one of the deadliest of its kinds. the instability is linked to the war in neighboring syria. turkey has the third war against i.s.i.l. it is also at war with the p.k.k. inside and outside the borders. the mainly kurdish south-east has been a battleground for months. as of late it launched ar till restrikes inside northern syria, a syrian kurdish armed group that ankara says is an offshoot of the p.k.k. turkey wants to prevent the y.p.g.'s expansion which it occurs a national security threat. turkey's national intelligence agency had warned of reprizal attacks in response to those on kurdish positions in syria our correspondent joins us live. any clearer yet who carried out that attack? >> reporter: turkish media close to the government is reporting

that this was the work of a suicide bomber from syria. the media not naming the organization, the bomber is affiliated with. cctv footage released showing a car approaching personnel which was waiting at a traffic light and the explosives were detonated. turkish officials not pointing the figure of blame on any organization yet promising to find the perpetrators as the investigations continue. we call the ministry to ask about these reports and so far they're refusing to confirm or deny these reports. yesterday we heard turkish officials call for unity saying the aim of the attack was to divide the nation, that it just didn't target the military, the country, the nation, the country's president, vowing a hash response saying turkey has the response to retaliate

whether it is inside or outside the country's borders. this attack was clearly a message to the government in the heart of the capital targeting the military of an area very close to the military headquarters as well as the parliament. it caused fear and panic in the capital for hours. scores of ashlts, 28 people killed, 38 people in hospital but they're with slight injuries. so this is not the first attack of its kind. turkey has seen four major attacks over the past months. previous attacks were blamed on i.s.i.l. but yesterday initial suspicion is calling on the p.k.k. turkish intel over the past few weeks were expecting some sort of attack. we have to remember turkey is at war with the p.k.k. and is now targeting shelling y.p.g. positions inside syria. turkey, of course, sees the

y.p.g. as an offshoot of the p.k.k. that turkey calls terrorists thank you for that. the united nations say aid trucks have reached several besieged towns and villages in syria. the deliveries are to people trapped in the area >> reporter: a ray of hope in the midst of war. over 100 trucks covering humanitarian aid spreading out towards some of syria's besieged towns. in madaya near the lebanese border they're bringing medical supplies and a mobile clinic as well aas food. thousands here are trapped by forces supporting bashar al-assad which court hezbollah fighters. aid workers say at least 40 people have died of malnutrition in the town since october. >> we have people to bring the medical support kits and make assessments for people in need that had have in food shortage.

>> reporter: this is heading to the north. around 20,000 people have been cut off by armed rebel groups. heavy gunfire is close to damascus. rebels guard the entrance to this city where trucks line-up carrying supplies for at least 30,000 people trapped here. more aid is expected to arrive in the east, parts of which are held by i.s.i.l. the convoys are part of an agreement reached last week by over a dozen countries, including the u.s. and russia. there is no deal to make sure the supplies keep coming and not all the towns under siege can be reached. why doesn't the northern countryside of homs get aid. they're to reach all areas. is the u.n. waiting for to ceasefires before the aid can enter?

>> reporter: homs has been a battleground for months. local supply routes have been cult off by a syrian government offensive. the u.n. says food shortages can get worse for the many who live here. the last aid to reach here was in october. in aleppo city is close to being besieged. a pause in the fighting has been agreed for the end of this week, but there's still no sign it will happen. an international task force will hold its first meeting on friday to discuss the practicalities of ending the hostilities in syria. first they need to regard who is on the international list of so-called terrorist groups the united nations spen envoy for yemen says talks to end the war must happen by march. negotiations were put on hold

last month. deep divisions exist which prevent me from calling talks. the parties are divided over whether a new round of talks shall be convened. i have not received sufficient assurances that a new ceasefire would be respected if called for voting is underway in uganda for the presidential and parliamentary elections. the president is seeking another term to extend his 30-year rule. his main challenger is former ally who is running against him for the fourth time. malcolm web is in the capital and joins us live from there. how is polling going now? i heard they got off to a late start. are things going more smoothly now? >> reporter: that's right. people did turn up earlier. people in the city are keen to vote. they have been at poling stations from about 6 o'clock

local times, but it started a few hours after that. in some places it still hasn't started. people are waiting for that to begin. here there has been a long line of people. there has been reports that their names are on a polling station that are not there. here agents representing the opposition candidate say that when they arrived here this morning they noticed discrepancy of differences between the previously published version of the voters registered for this polling station and the one that is here today. they say names have been added, but when this issue was raised they were apprehended by agents from the ruling party and taken away by police. we have spoken to the agents here from the ruling party saying those opposition members were trying to cause trouble and anyone who tried to do that, the polling stations would have to be stopped there were predictions about

rigging before polling stations opened. how free and fair are these elections been seen by people there? >> reporter: there's a lot of complaints here in the capital city which is, of course, an opposition stronghold. a lot of people supporting the opposition complain that there's high risk of vote rigging and irregularities. the electoral commission denies it and the government says this poll will be free and fair and the measures taken are to preserve security and prevent unrest. another thing that is undermining people's confidence is the fact that social media sites have been blocked on most of the mobile networks. it is not possible to access twitter and facebook, so a lot of people who have do have access, that's not instilling confidence. we've tried to speak to the communications commission. we haven't got any comment about why these services have been

closed down tell us more about the main challengers. >> reporter: he is now running against the pt for the fourth time. he has been declared in the last three elections. he alleged they were rigged. he says more support now than ever before and he can do it. he has urged his supporters to vote early and stay at the polling stations to guard their stations until poling closes and counting begins. the next is a former long time ally of the pt. he was the previous prime minister. because of his many connections within the ruling party it is thought that he has a lot of

influence. those opinion polls are disputed by the opposition who say that they're not accurate and they're not credible. what we're seeing today and what we will be seeing in the media here in the capital, it is worth remembering 85% of people living in rural areas. that's where the outcome of this election will be decided. all parties claim that they have the rural votes, they have the wide yeft support base-- widest support base thanks for that. still to come. >> reporter: i'm in singapore. coming up we will tell you how territorial dispute in the south china sea are prompting a rapid military build-up-- rapid military build-up.

welcome back. let's remind you of the top stories. turkey's presidential is vowing retaliation after a car bombing in the capital. a military convoy was hit close to parliament. at least 28 people were killed and 61 wounded. the u.n. says aid is being distributed in some besieged areas in syria. trucks carrying food, water and medicine to nearly 100,000 people reached villages and towns on wednesday. ugandans head to the polling booth to cast their votes. the president is seeking another term to extend his 30-year rule.

u.s. secretary of state john kerry says increasing evidence of militarization of by china in the south china sea is a serious concern. beijing is downplaying reports it has deployed surface to air missiles to the contested island. kerry says there will be more talks with china in the coming days. several countries lay claim to the territory and the resource rich region. the regional tension is part of the reason for a spending spree in asia's largest defense and air show in singapore. scott heidler joins us from the singapore air show. how are the big spenders splashing the cash there now? >> reporter: they're definitely here and in big numbers as are the companies who paracel the dwoens products, if you will, that those countries are so desperately seeking out. when we look at the militarization of the south china sea, that that has been

accusations going on for the last several months. there are other nations beefing up their militarization in this region. >> reporter: the sky over the south china sea is becoming crowded. several nations, including vietnam, philippines and malaysia are accusing china of moving in on their sovereign territory. china refutes this saying 90% of the south china sea is theirs. what is undenialable is that the increasing tension has led to a military buying spree. >> i think china's military expansion, the increases and its actions in the area have, in fact, triggered something of an arms race. >> reporter: a united states military footprint in the region

is not new, but it has been growing over the last several years. >> militarization of the south china sea and particularly the artificial islands that will be used for military purposes by china is a concern for the u.s., but it doesn't pose a threat. >> reporter: the u.s. wants its presence felt. general robinson commands all u.s. air forces in the region greeting staff at the air show >> i can't tell you how much it means to me to see all the joint air power, what we're doing as team america and being out here to show our commitment >> reporter: part of that show of strength why the region is this, the p8 poseidon, one of the most sophisticated airplanes. >> whether it's singapore or the

philippines, you can within a short amount of time we with put a jet there and support our regional allies >> reporter: the philippines has taken its territorial dispute with china to the hague. it announced it is buying $100 million dollars of equipment to boost maritime security. if the situation in the south china sea continues, the region could remain one of the defense industries dream markets for years to come. >> reporter: we're going to speak with the asia bureau chief of defense. tell us more. when we look at the militarization particularly with china and this move by them to locate missiles there, what does it do to the tensions in the south china sea? >> it frustrates the neighbors who have claims on those islands and also frustrates the

americans as well because there is very little the americans can about it. we don't have the capabilities any more to engage china in a military basis. during the cold war we had bases in vietnam, cambodia, thailand and philippines, but all of these are gone now. their ability to protect this area from an outside power, really not an outside power at all. china is basically filling it vacuum of security. they claim that south china sea islands and they're going to push until they own them >> reporter: if we look at other things, what is going on in the north korea/south korea border, china as hay ale role in that, u.s. had also, do you think it is a tit for tat move? >> i don't think they're related

necessarily. the south china sea, they're protecting their assets and demonstrating their capabilities to do what they have to do to keep them. u.s. have been flying military aircraft over those islands, frustrating them, irritating them, and they've moved air defense systems there. that's not a big supplies. on the north korea/south korea thing, the missiles are thaad designed to protect you. china has no complaints. if i point a gun apt you and you buy a bullet-proof vest, i can't complain. it is a natural order of things. >> reporter: thank you for that. obviously, if those two incidents are not directly connected there is still, when you look at the south china sea, a lot of defense buying going on thanks for that. the white house is trying to calm people's concerns about

security after an f.b.i. request to apple to access the phone of one of the san bernardino attackers. >> reporter: u.s. president obama a mounting a task force to improve the government's cyber security >> the poll in the last few days showing that the american people understand that this is a problem >> reporter: there is one area that his government is saying data is too secure. they're trying to get apple to disable a security feature on the iphone. investigators want to open one of the phones. >> they are not asking apple to redesign its product or to create a new back door to one of their products. they're simply asking for something that would have an

impact on this device >> reporter: critics say that's misleading >> you say only for one phone, but it's not possible to create software that only applies to one phone. if apple were to create software and give it to the f.b.i. to put it on the phone, that would be a master key that could be applied to millions of phone around the world >> reporter: apple has built a system of encryption that they can't hack >> if they could provide the data, then it will be obligated to apply. that could be an order from the u.s. or any country in which apple does business, including a country that might not be favorable to the u.s. >> reporter: this case has the potential to impact cell phone users across the globe >> this is the technology that is deployed all over the world. apple is very reluctant to create that technology. we see the same pressure around the world, but this is escalated

up to maybe the supreme court in the u.s. to make a final decision about what is required to comply with the u.s. law >> reporter: the basic question, should the government able to get information off your smart phone. the answer in the u.s. could have an impact worldwide venezuelan has raised petrol prices from 2 cent to around 94 cents a litre. it is the first rise in 20 years. the president says the hike is needed to balance the economy. he also devalued the currency. petrol is heavily subsidized in the country. government revenues have fallen sharply because of low oil prices. >> reporter: people here are expecting that these measures will somehow ease the tension that has been building up for the last couple of years. it is combhon to see people lining up for hours outside foot shops and even then going in to

find that shelves are bear. it is expected that freeing up some of these price controls food would again start appearing in market shelves. perhaps the most meaningful decision that the president took was to raise the price of gas or gasoline. this is the first time in 20 years that a venezuelan government has decided to raise the price of petrol. in 1989 a similar decision meant that people took to the streets and rioted for three taste or more. this was the first time in venezuelan which was considered to be the longest standing democracy that in the event that this occurred, so after that haven't the whole idea of raising the price of petrol here has become pretty much taboo. the president has asked for people to remain calm.

as soon as the president announced that this increase of as much as 6000% was to take place, people started rushing to petrol station to fill up their gas tanks. it is unclear whether they wanted a one last chance or somehow afraid of a repeat of the events 27 years ago of looting and violent protests in the streets pope francis has finished his five-day trip to mexico with a mass on the country's border with the u.s. the pope has been very critical of both the political and church elite in mexico. he says they need too more for the people living amongst corruption and violence. >> reporter: a prayer for thousands of migrants who have died trying to reach the u.s. pope francis finished his trip to mexico with a mass just metres away from the u.s. he has long been a supporter of

migrants and admonished rich countries to do more. >> translation: the human tragedy that has forced migration is a global phenomenon today. this crisis, which can be measured in numbers and statistics, we want instead to measure with names, stories and families. >> reporter: hundreds of thousands attended the ceremony. thousands more watched on cctv over the border in texas. his support of migrants stands in contrast to rhetoric by republicans running for presidency. this was once the most violent city in mexico. people were touched by his visit here >> translation: we're hurting as a city with so much violence, so much fall out from the violence. so many children and youth, so many who have lost their way and many families that fled were still here giving it our all.

>> translation: we're hoping for peace to arrive because of all the violence we've had had. we ask him to bless our city and the whole world, but especially here so there won't be so much violence. >> reporter: earlier in the day hope francis visited the prison that was once run by drug gangs and was the scene of deadly riots in 2009. he was able to show he wants to reach out to those discarded by society, prisoners and migrants, people that politicians and church leaders often want to overlook. it was the final stop on a five-day visit that took him from the southern tip of mexico to the northern border. along the way he criticized politicians who oversee governments that allowed criminal gangs to flourish. he also criticized leaders who did not stand over their flock.

still, millions of people feel he stood with him as they looked for a way to break free from years of corruption and violence if you want to follow more details on all those stories, just head over to our website at aljazeera.com >> thanks for joining us on "america tonight." i'm joie chen. modern medicine has often done the impossible. creating technologies to make people stronger, healther than ever