Q+A - What's the real threat of North Korea's nuclear programme?

By Jon Herskovitz

SEOUL (Reuters) - North Korea said on Monday it had conducted a nuclear test, the second for the secretive state after a 2006 blast that was seen by experts as only a partial success due to its relatively low yield.

Pyongyang had threatened a new nuclear test in response to tightened U.N. sanctions.

Following are some questions and answers about the secretive state's nuclear arms programme:

WHAT IS NORTH KOREA'S NUCLEAR WEAPONS CAPABILITY?

North Korea is thought to have produced enough plutonium for about six to eight weapons and has already produced one rudimentary nuclear device. It likely cannot miniaturise a nuclear weapon to mount on a missile and would need a significant amount of testing to master the technology, weapons experts say. And its Soviet-era bombers would not be able to evade the advanced air forces of the United States, Japan and South Korea to deliver a bomb, which means it may be many years before North Korea can actually threaten the world with a nuclear weapon.

SO HOW BIG IS THE SECURITY THREAT?

The North's nuclear arms programme is not a major security threat at present because it has not yet shown it can build an effective bomb, nor does it have an effective delivery system.

Results that show the explosive force of the current test should be known in the next few days, which will indicate if the country has improved its nuclear weapons technology.