The White House Wednesday charged Republican "stunts" and "hypocrisy" were endangering US security after its political foes launched a new bid to block a new nuclear pact with Russia.

The Obama administration was particularly incensed at a call by Republican Senator Jim DeMint for the entire treaty to be read aloud to lawmakers, in an clear attempt to stop the pact being endorsed by the Senate this year.

"This is a new low in putting political stunts ahead of our national security, and it is exactly the kind of Washington game-playing that the American people are sick of," said White House spokesman Robert Gibbs.

"While some express concern that the Senate doesn't have time to debate the treaty, Senator DeMint wants to waste 12 hours to read the text of a treaty that has been available to every member of the Senate and the public for more than eight months," Gibbs said in a statement.

Gibbs said the treaty, which makes large cuts in the number of nuclear weapons deployed by Russia and the United States, had been the subject of 20 Senate hearings and 1,000 questions.

He noted the Strategic Arms Reduction Treaty (START) was backed by former president George H.W. Bush, every living Republican secretary of state, NATO allies and the Pentagon.

"Every minute that the START Treaty is being read on the Senate floor increases the time that we lack verification of Russia's nuclear arsenal," Gibbs said.

"It is the height of hypocrisy to complain that there is not enough time to consider this treaty, while wasting so much time reading aloud a document that was submitted to the Senate months ago."

The new Republican blocking tactics emerged as the Senate moved to open formal debate on the pact, racing the clock before the current congressional mandate expires early next year.

Obama has made the new treaty, agreed with Russia this year, the lynchpin of his drive to "reset" relations with Moscow.

Democrats control 58 Senate seats and need nine of the 42 Republicans to reach the 67 votes needed for ratification, but would need 14 Republicans when a new Congress convenes in January that reflects November mid-term election results.

Republicans -- led by their number-two, Senator Jon Kyl -- have vowed to block ratification in 2010 and planned to force potentially politically painful votes on "treaty-killer" amendments that stood virtually no chance of passing.