PART2

It has a crude multi-stage design and poor guidance system and takes weeks to prepare for launch. U.S. spy satellites can easily monitor the preparations and it should be relatively easy to destroy long before launch.

Experts have said North Korea does not yet have the technology to miniaturise a nuclear device to use as a warhead. But the North has been working on placing biological and chemical weapons on missiles.

WHY WOULD IT TEST A SHORT-RANGE MISSILE?

North Korean short-range missiles, thought to number in the hundreds and with ranges of about 100-150 km (60-95 miles), can hit all of the Seoul area and many U.S. military bases in South Korea. They have been successfully tested.

North Korea times its short-range missile launches for periods of increased tension to send political messages. A launch would be intended to grab the attention of new U.S. President Barack Obama and could dominate the agenda of Secretary of State Hillary Clinton, who is making a trip to Asia next week.

The North is also trying to put pressure on South Korean President Lee Myung-bak, who took office a year ago and has angered his destitute neighbour by cutting off what once had been a free flow of unconditional aid.

WHAT ABOUT ITS MID-RANGE MISSILES?

North Korea has several hundred Rodong missiles, with ranges that can hit all of South Korea and most of Japan. A launch of one of these ballistic missiles would violate international provisions and be much more provocative than a short-range test.

WHAT DOES NORTH KOREA RISK BY TEST-FIRING THE MISSILES?