"This is typical North Korean tactics," says Kim Sung-han, professor of international studies at Korea University. "When North Korea is interested in negotiating a certain issue, they need to create tensions." Its central interest now, he says, is "sending a message to the US, and to South Korea too, before the Obama administration finishes its policy review."
South Korea's conservative president, Lee Myung-bak, is trying to win assurances of the Obama administration's full support. He has pursued a hard-line stance since taking office a year ago, cutting off aid that South Korea had delivered for years to North Korea.
While aware of concerns about recent North Korean "threats," Mr. Lee said Monday in a radio address, "you do not need to worry too much."
US intelligence analysts estimate the North has fabricated six to a dozen warheads but doubt the North has the capacity to deliver them to targets.
Satellite imagery last week showed that North Korea had transported a Taepodong-2 missile, with a range of several thousand miles, to the site from which a Taepodong-2 was launched unsuccessfully in July 2006. That missile arced into the sea after a flight of 40 seconds.
"They are moving parts, assembling it," says Mr. Kim. "Then they will be putting fuel into the missile. It's a salami tactic. They are not going to launch it immediately."