Dr Rice said freed inmates could go on to jeopardize countries' security
US Secretary of State Condoleezza Rice has urged countries that have nationals who are inmates at Guantanamo Bay to help the US close the detention centre.
She told the BBC that such countries could guarantee the "bad people" held there would not be a danger if freed.
Ms Rice repeated the expressed wish of US President George W Bush's administration to shut the camp.
But she said it must not be done at the expense of the safety of Americans and other people around the world.
She said the detention centre contained dangerous men who had been caught on the battlefield in Afghanistan and had been plotting against capitals in the US, Europe and South East Asia.
BBC Washington correspondent Jonathan Beale asked Dr Rice if the US had plans to close the detention centre.
She replied: "Of course we would like to see Guantanamo close - there's only one problem: what are you going to do with the bad people who are there?
She added: "What are we going to do with them? Release them again on an unsuspecting population? I don't think so.
About 300 prisoners are still held at Guantanamo Bay
"One of the things that would help a lot is, in the discussions that we have with the states of which they are nationals, if we could get some of those countries to take them back ... and take them with constraints that ensure that they are not going to be a danger to society again.
"So we need some help in closing Guantanamo.
"Of course we'd like to do it, but we're not going to do it at the expense of the safety of Americans and other citizens."
About 300 prisoners are held at Guantanamo Bay, which was set up at a US naval base in Cuba in early 2002 after the invasion of Afghanistan.