John Bolton

The United States has proposed stringent United Nations sanctions in response to North Korea's apparent nuclear test.

U.S. Representative to the U.N. John Bolton said Monday the proposal includes inspecting all cargo going into or out of North Korea to check for weapons of mass destruction or related materials, a total arms embargo, and a freezing of assets connected to Pyongyang's weapons program.

Earlier, the council condemned the test in general terms, but U.N. legal experts were to have met later Monday to consider specific actions.

The United States, Britain and France are pushing for sanctions against North Korea under Chapter Seven of the U.N. Charter -- a section that mandates a council response to threats to international peace or acts of aggression.

North Korea's U.N. ambassador, Pak Gil Yon, said the Security Council should congratulate the North instead of passing what he called "notorious, useless" resolutions.

A White House spokesman, Tony Snow, says it could take up to two days to confirm North Korea's claim to having conducted a nuclear test.

International monitors confirmed that a seismic tremor detected Monday morning in northeastern North Korea suggested a nuclear blast.

U.S. intelligence officials estimated the blast's size at less than 1,000 tons of T.N.T., and said they have not yet determined if it was nuclear.

Russian officials estimated the blast may have measured as much as 15,000 tons of T.N.T., about the same size as the atomic bomb the United States dropped on Hiroshima, Japan, in 1945.

South Korean intelligence officials said there are indications the North may be preparing another test.

South Korea has raised its military alert level, and its president convened an emergency security meeting. The Korean peninsula has been particularly tense since Saturday, when South Korean forces fired at North Korean troops who crossed the Demilitarized Zone.

e Some information for this report provided by AP and Reuters.