Analysts believe Kim working on H-bomb

If Kim Jong un is to reach his ultimate goal, experts say the world can expect more nuclear tests from North Korea.Pyongyang's weapons program is developing rapidly but it still has to perfect a nuclear warhead small enough fit on the tip of a rocket, fly over vast distances, and survive re-entry without burning up.Analysts say that's a long way off and the only way to perfect it is more rocket and nuclear testing.North Korea claims its missiles can reach any part of the U.S., but according to analysts, they only way that could be true is if they've been testing their missiles with a lighter payload than any nuclear warhead it can make right now.That could mean Kim's scientists are ultimately working on a hydrogen bomb, which has the potential to deliver a bigger boom in a smaller package.But carrying out testing for an H-bomb means Kim needs to make some careful decisions.Further nuclear testing would be sure to have consequences, from tougher UN sanctions to the threat of a U.S. military action, not to mention angering it's only real ally, China.That could be why Washington doesn't expect an imminent test.U.S. officials tell reuters that although North Korea's only known nuke site has been rigged up for several months, there's no clear sign of plans for an upcoming launch.Still, South Korean experts see a sixth nuclear test as inevitable, because it's the only way for the north to ensure the survival of the Kim regime.