The US government has said it is relying on diplomacy to head off the suspected test, but there has been speculation it might use its fledgling missile defense system to shoot down an incoming missile if it is fired.

In New York, US Ambassador to the United Nations John Bolton said the US had approached the North Koreans last weekend "and told them that we thought the idea of a launch was a very bad idea."

Pyongyang has said it is willing to talk to the United States about its missile concerns, repeating its long-held desire for direct meetings with the Americans. Washington, however, has refused, insisting it will only meet the North amid six-nation talks aimed at ridding Pyongyang of its nuclear weapons program.

Aso said Sunday that the North's brinkmanship would not help it reach its goal of direct negotiations with Washington.

"How can you put up a rocket and then demand talks? That's intimidation, and makes it most difficult for America to engage in talks," he said.

The six-country nuclear disarmament talks - which involve the two Koreas, the US, China, Japan and Russia - have been deadlocked since November.

The North shocked the world in 1998 by firing a missile that flew over northern Japan and into the Pacific Ocean. It has been under a self-imposed moratorium on long-range missile tests since 1999, but has since test-fired many short-range missiles.

South Korean Foreign Minister Ban Ki-moon, who hopes to visit Beijing in the coming days for talks, said China has an important role to play in resolving the crisis.

"I will ask China to actively persuade North Korea," Ban said Saturday, according to South Korea's Yonhap news agency.

China, a key provider of aid to impoverished North Korea, is believed to be the only country that has considerable leverage with the North.

Venezuelan President Hugo Chavez, who has built ties with Pyongyang while clashing with the US, said Friday that he will make an upcoming trip to North Korea to finalize bilateral agreements in science and technology. He did not say when he would travel or what the agreements would be.

"This is not a secret trip," Chavez told reporters in Panama.