Republicans, pushing to pass a $447 billion bill for defence programmes, planned a procedural vote that could kill a Democratic amendment demanding Attorney General John Ashcroft turn over documents on the interrogation and treatment of prisoners.

But because some Republicans are also urging the White House to make a full disclosure of its policies on prisoners, party leader hoped to avoid putting senators on record as directly opposing the amendment, while still defeating the Democrats.

"The Senate Republicans are trying to stonewall the release of Justice Department memoranda on the torture of prisoners," said Senator Edward Kennedy, a Massachusetts Democrat.

Under pressure from lawmakers, the White House on Tuesday released a thick file of newly declassified papers to try to demonstrate that Bush and his top aides insisted that detainees at Guantanamo be treated humanely.

But Democrats said the documents were largely irrelevant, and said the White House should make a full disclosure.

The Senate Judiciary Committee on a party line vote last week rejected a Democratic proposal to subpoena 23 documents from the Justice Department they said should be part of an open examination into the abuse of US-held prisoners in Iraq that has drawn worldwide condemnation.

Senator John Cornyn, a Texas Republican, accused Democrats of playing "Beltway games and political tricks" in demanding "an extraordinary amount" of documents in addition to those released by the White House.

But Senator Patrick Leahy, a Vermont Democrat, said a vote to block the Democrats' amendment in effect said "We want to allow the administration to keep on hiding documents."

In other action on the bill, senators rejected 50-48 an amendment pushed by Kennedy calling for a prompt report from the White House on the number of US troops it expects to have in Iraq by the end of 2005, and its plans to get more international peacekeeping help.