And a House Democrats' report says the Bush administration has missed one opportunity after another to improve the nation's security.

The recent political rupture between Russia and the US only makes matters worse, said Lee Hamilton, the former Indiana Democratic congressman who helped lead the 9/11 Commission and now chairs the independent group's latest study.

Efforts to reduce access to nuclear technology and bomb-making materials have slowed, thousands of US chemical plants remain unprotected, and the US government continues to oppose strengthening an international treaty to prevent bioterrorism, according to the report produced by the bipartisan Partnership for a Secure America.

The group includes leaders of the disbanded 9/11 Commission, the bipartisan panel that investigated government missteps before the 2001 terror attacks on the United States.

"The threat of a new, major terrorist attack on the United States is still very real," concludes the report to be released on Wednesday, the same day a congressional commission will hold a hearing in New York on nuclear and biological terrorism threats.