The United States will decide in the coming weeks whether to take the North Korea nuclear issue to the United Nations, where sanctions could be imposed.
A senior U.S. defense official said Sunday that Washington is considering taking the matter to the world body because U.S. officials do not see any effort on the part of Pyongyang to cooperate.
The official, speaking on the sidelines of a security conference in Singapore, described the North's statements on the nuclear issue as "a downward spiral of threats."
The senior U.S. defense official made the comments to reporters on condition of anonymity.
South Korean President Roh Moo-hyun will meet President Bush in Washington on Friday for talks on the nuclear issue.
Pyongyang has threatened that any U.N. sanctions would be considered a declaration of war.
Some information for this report provided by AP and Reuters.