Tony Blair is coming under pressure to urge the US to close the Guantanamo Bay detention camp after one of his Cabinet ministers said it should be shut down.
Some inmates have been at the detention camp since 2002
Peter Hain said he would prefer to see it closed and thought Mr Blair agreed.
Lib Dem leadership hopeful Sir Menzies Campbell urged Mr Blair to act on a new UN report saying aspects of the regime at the camp amounted to torture.
Mr Blair only repeated his stance that the camp was an "anomaly" that should be dealt with "sooner or later".
Time to close?
In the wake of the UN report, Northern Ireland Secretary Mr Hain told BBC One's Question Time: "I would prefer that it wasn't there and I would prefer it was closed."
Asked if Mr Blair agreed, Mr Hain said: "I think so, yes."
Mr Hain's comments follow a critical UN report on the camp
The prime minister was asked about the controversy after talks in Berlin with German Chancellor Angela Merkel.
He said: "I've said all along... that it [the camp] is an anomaly and sooner or later it's got to be dealt with."
But he did not expand on what he has previously told MPs.
Sir Menzies, the Lib Dem foreign affairs spokesman and acting leader, is writing to Mr Blair asking him to urge the US either to put the prisoners in Guantanamo Bay on trial or release them.
"The systematic violation of human rights undermines the moral authority of the West and makes it impossible to win the long-term battle for hearts and minds," he said.
"It is time for the prime minister to take action and to demand the closure of the camp. Detainees should either be charged or released."
The nine Britons who were held at the camp have all been released but three former British residents remain as detainees.
Sir Menzies is also asking what representations the UK has made to the American authorities about them.
The three men have won permission to seek a High Court order requiring the UK to petition for their release.
A judge said claims of torture at the camp meant the government might have an obligation to act on their behalf.
But there were "formidable arguments" against Bisher al-Rawi, Jamil el-Banna and Omar Deghayes's case, he added.
The judge, Mr Justice Collins, remarked during the hearing on Thursday that America's idea of torture "doesn't appear to coincide with that of most civilised countries".
Speaking too quietly?
Conservative shadow foreign secretary William Hague is in Washington to build bridges with the White House.
He used a speech to warn reports detainees were being mistreated damaged the "moral authority" of the US-UK alliance.
Chairman of the Commons foreign affairs select committee, Labour's Mike Gapes, welcomed Mr Hain's comments and said there was a feeling among MPs that a "more forceful statement" should be made about the camp.
Asked on BBC Radio 4's Today programme why he thought Mr Blair was not being "bolder", Mr Gapes said: "I suspect it's part of a general approach to speak quietly to the Americans and not make big public statements."
Responding to the new United Nations report, UN Secretary General Kofi Annan, said he hoped the US would close the camp as soon as possible.
But the US government described the document as "a discredit to the UN".
White House spokesman Scott McClellan said investigators had failed to examine the facts and their time would be better spent studying other cases.