tina krause has more now, from london. >> senior un inspectors a they hope this trip to tehran will bring some answers. >> reporter: their visit last month did little to calm world tensioned over iran's nuclear program. this time monitors are pressing iranian officials to give them more access. they want to speak to iranian nuclear cine scientists and visit a key facility to find out whether iran is trying to build an atomic bomb. iran's national guard started war games over the weekend to show the world iran is prepared to defend itself, if needed. tensions are high with israeli officials threatening a possible strike on iran's nuclear facilities. both the u.s. and britain are urging israel not to launch an attack saying there is no proof iran is developing a nuclear weapon. >>> they think a strike by israel would be large, complicated and probably counter productive. >> reporter: a conflict could push already spiking oil prices through the roof and speed up iran's nuclear ambitions, instead of stopping them. on sunday iran stopped selling oil to british and french companies, head of eur

tina krause has the latest developments now from london. >> reporter: hundreds of protestors loyal to syrian president bashar al-assad tried to storm an international conference in tunisia. foreign ministers from more than 50 countries are meeting to demand an end to the violence in syria. u.s. secretary of state hillary clinton is among those at the friends of syria gathering. she's calling for a cease fire to allow humanitarian aid into the country. and pressing for new sanctions and travel bans. gunfire gunfire [ sound of gunfire ] , rebels are locked in a fierce battle with syrian government forces, they're asking international leaders to send them more weapons to help take down the assad regime. activists say syrian troops executed at least 18 people in a village of central via friday including at least -- syria friday including at least five children. the humanitarian chief in the u.s. says the situation is deteriorating and the syrian government is blocking aid. >> we have -- that appear to be under siege and what we're desperate to do is to try to get a proper assessment of wh

tina krause reports. >> syrian forces reportedly shelled a house in the rebel house, killed an american reporter. 57-year-old marie was a veteran correspondent for a british newspaper. the new york native lost an eye covering another war more than a decade ago. >> this is a desperately sad reminder of the risks that journalists take to inform the world of what is happening and the dreadful events in syria. >> just a day before she died, she was on tv saying it was shocking. >> the sickening thing is the complete merciless nature. they are hitting civilian buildings. >> a french photographer was also killed. witnesses say a rocket hit the journalist as they tried to escape a barrage of shelling. helicopter gun ships are helping forces. weeks of attacks left hundreds dead. this amateur video reportedly shows hundreds of syrian soldiers joining the fight to take down assad's government. western powers, including the u.s., have not ruled out arming rebels to help end the conflict. tina krause, cbs news. >> now reporters without borders maintains that syrians are targeting journalists to try

tina krause, cbs news. >> that riot came on the one year anniversary of one of the most violent days in the uprising against mubarak when loyalists rode camels through tahrir square attack the protesters. >>> the occupy d.c. protesters at mcpherson square say sleeping is a right and they continue to defy the park police ban on camping overnight in the park, but officers have yet to arrest anyone. meanwhile some conservatives say they will soon take back another occupy site, freedom plaza. the conservatives are part of the national center for public poach research. they say they have a -- policy research. they say they have a permit to reclaim half of freedom plaza. the think tank plans to rally at freedom plaza february their tonight. >>> a 750 year copy of the magna carta has received a facelift. today the national archives unveiled the newly refurbished version today. philanthropist david ruben symptom stein funded the conservation -- ruben stein funded the conservation efforts with a gift. he's the same man who donated money to repair the washington monument and to save the nation