The White House on Friday denied that the United States or its allies had issued "warnings" to North Korea not to fire a missile thought to be able to reach the United States. Spokesman Tony Snow's comments came amid an apparent effort by US officials, including Vice President Dick Cheney, to downplay the possible threat posed by the North Korean missile.

"If you listen to comments made in recent days by the government of Japan, the government of China, the government of South Korea and the Russians, also, they've all said to the North Koreans, 'you shouldn't fire a missile,'" spokesman Tony Snow told reporters.

"That is not a warning, that is a piece of advice," he said. "And the United States has said all along, we have not issued warnings, what we have said is it would not be constructive."

Japan has said it will "take severe action in discussion with the United States" if the missile is launched, while the United States has said it will "seek to impose some cost on North Korea."

Preparations for the launch of a multi-stage Taepodong-2 with a range of up to 6,700 kilometers (4,200 miles) have been underway for several weeks at Musudanri on the remote northeast coast of North Korea. US reports have said a launch is imminent.

"This is not the United States versus North Korea," said Snow, who urged North Korea to return to six-country talks aimed at ending the crisis over Pyongyang's nuclear programs.

The problem, Snow said, is that North Korea is "not a transparent society. So the idea that somehow we know what's going on in the minds of Kim Jong Il or others; we don't. And it's one of those things."