is said in the past that it wants to avoid the korean peninsula being knew clee arised arised-- nuclearised. the big worry for the rest of the region, particularly the united states, in particular, is whether this test, this h bomb test today, could be the first step to bringing the north closer no developing a war head, a nuclear war head, that could be mounted on a long range missile that could reach the united states. that will be the big worry in the united states today >>> thank you. what exactly is a hydrogen bomb and how does it work? it's the most powerful type of nuclear bomb. in some cases it can reach more than 2,000 times the of the nuclear bombs which were dropped by the u.s. on the japanese cities in the 1940s. unlike atomic bombs which release energy by breaking apart, a hydrogen bomb derives its explosive force from nuclear fusion. it produces extreme heat and can spark fire storms and intense white light that can induce blindness. a professor says testing bombs is a way for north korea to ignore natural it wants-- signal it wants something from the international community.

. >> beijing opposes the nuclearisation of the peninsula but it has not opposed any of the sanctions. >>> the widow of a man killed in the shooting in san bernardino file as $58 million claim. a lawsuit. her husband was one of 14 people it was during a holiday party at the inland regional center. she is asking for $3 million from the county. 25 in damages 167,890,000,000 for their children. her husband's death was preventable. a spokesperson said the county will consider each claim. >>> and developing right now from oklahoma, a fire at a plant southwest of oklahoma city. several of the holding tanks there have caught fire. these are just into the newsroom. trucks are burning. smoke are billowing up. and highways have been shut down because it is thick. we're not sure but we'll follow it. >> a suspect leads police on a slow speed chase across four counties in texas today. officials spotted a stolen 18-wheeler in garland, outside of dallas. when the driver refused to pull over the chase started. the police had to use spike strips. it did not stop. the driver ran out a s.w.a.t. surrounde

steps necessary to get to the achievement of the goal, to the negotiations that result in de-nuclearisation ( translated ): in order to maintain peace and stability on the korean peninsula, we have to first achieve de-nuclearization there. and only through negotiations will we eventually achieve de- nuclearization on the peninsula. sanctions are not the goal. the key is to resolve problems. >> woodruff: china is north korea's lone major ally, but the u.s. has complained that beijing is not using all the leverage it has to influence the country. >> ifill: back in this country, the governor of michigan is defending his response to the lead contamination crisis in flint. republican rick snyder visited the city and announced an advisory group to recommend long-term fixes for the water system. but at a news conference, snyder deflected criticism that he isn't doing enough to reach out to the people of flint. >> i'm looking to do teletown halls where i can get on the phone with people and have them ask their questions. the citizens of flint because i do care about the citizens. >> so, will that b

to fulfil de-nuclearisation, nuclear non-proliferation, peace and stability on the korean peninsula isna's firm stance. >> ifill: whether it was really a hydrogen bomb was also widely questioned, especially in neighboring south korea. >> ( translated ): judging from the measurements, it probably falls short of being a hydrogen bomb, although north korea claims it's a hydrogen bomb. >> ifill: in washington, white house spokesman josh earnest said the u.s. is skeptical, too. >> the initial analysis that's been conducted of the events that were reported overnight is not consistent with north korean claims of a successful hydrogen bomb test. there's nothing that's occurred in the last 24 hours that has caused the united states government to change our assessment of north korea's technical and military capabilities. >> ifill: meanwhile, japan's government immediately sent an aircraft out to collect air particles for radiation analysis. a working hydrogen bomb would be hundreds of times more powerful than what north korea detonated in three earlier underground tests. and, it might fit on a m