The U.S. Senate has issued a sharp rebuke to the administration of President George W. Bush over its policies in Iraq and its treatment of detainees.

It also told the Iraqi government that it's time Iraqis started running their own country and fighting their own war.

Among the series of bipartisan votes passed by the Senate on Tuesday were demands for a war update from the White House every 90 days and some kind of troop redeployment – if not withdrawal – in 2006.

Senator Joseph Biden

The Republican-dominated Senate also voted to ban all forms of torture and gave limited appeal rights to prisoners being held at Guantanamo Bay.

The bipartisan effort was seen as a clear signal that even Republican senators were willing to break with the president, as public support for the war slumps and many legislators embark on an election year.

'Tell us, Mr. President, what's the plan?'

Senator John McCain

"What I think all Democrats and Republicans have finally decided to do is [say], 'Tell us the plan, Stan,'" said Senator Joseph Biden, the Delaware Democrat who heads the Senate foreign relations committee. "Tell us, Mr. President, what's the plan?"

It was a day of strong words from Republicans as well, including from one of the deans of the Senate, Virginia's John Warner.

Warner said that, after an enormous sacrifice of life and limb by U.S. military forces, it was time for Iraqis to pick up the burden of running their own country.

"The basic purpose of these amendments is to send the strongest possible message to the Iraqi people," he said.

"We mean business. We have done our share. Now the challenge is up to you."

The Senate was tucking into the corners of a massive Pentagon spending bill what amounted to its first serious challenge of the Bush administration's conduct of the war in Iraq.

Although the Senate rejected a Democratic demand for a timetable for the withdrawal of troops from Iraq, it voted 79-19 on a Republican proposal that urged 2006 "should be a period of significant transition to full Iraqi sovereignty."

It also called on the Bush administration to outline its strategy for ending the Iraq campaign and demanded that the White House give war updates to the Senate every three months.

Senate defies White House with torture ban

The Senate issued an even sharper rebuke to the administration over the U.S. military's treatment of detainees in the aftermath of the Sept. 11, 2001, attacks in the United States.

Senator John McCain, a Republican from Arizona – with the strong support of virtually every senator – managed to include in the spending bill a measure that bans torture.

It also restricts interrogations and bans the use of cruel, inhuman and degrading treatment of foreigners in U.S. custody, in accordance with international law.

"Nothing hurt us more than I can think of than the Abu Ghraib pictures that ran 24/7 on Al-Jazeera," said McCain, referring to notorious photographs of U.S. soldiers abusing and humiliating inmates at the Abu Ghraib prison in Iraq.

• INDEPTH: Abu Ghraib

The White House has strenuously opposed such measures, even sending Vice-President Dick Cheney to Capitol Hill to lobby that the Central Intelligence Agency be exempted.

"A clear and firm commitment on the part of the U.S. government that we will not only not torture but we will not treat people in a cruel or inhumane fashion is absolutely vital," said McCain, a veteran who was brutally tortured by the North Vietnamese.

Guantanamo detainees given limited legal rights

The Senate also waded into another area that until now had been the exclusive domain of the White House: the legal rights of military detainees.

For the first time, lawmakers agreed that detainees held at the U.S. naval base in Guantanamo Bay, Cuba, and elsewhere should have a right – albeit a strictly limited one – to appeal to federal courts.

They would be allowed to challenge their convictions under military tribunals – which don't follow the normal rules of evidence and due process – and their status as "enemy combatants."

However, the senators opted to otherwise uphold an earlier vote that removed most other legal rights from the approximately 500 people who are being held at the Guantanamo Bay detention centre.

Many of the men – who were mostly captured in Afghanistan or in Iraq during the U.S. administration's so-called "war on terror" – have been held there for as long as four years without being charged or having access to the alleged evidence against them.

The provisions approved by the Senate may not become law. They will have to survive the negotiations between the Senate and the House of Representatives to make it into a final defence bill.