No torture of terrorist suspects? We can't guarantee it, says Rice

"Will there be abuses of policy? That's entirely possible," she said on a visit to NATO headquarters. "Just because you're a democracy it doesn't mean that you're perfect."

But she offered assurances that any abuses would be investigated and violators punished.

"That is the only promise we can make," she said. She was speaking a day after trying to clarify to European foreign ministers the US policy on secret prisons and treatment of terrorism suspects.

The ministers appeared receptive. NATO Secretary General Jaap De Hoop Scheffer said Ms Rice had "cleared the air". He said she had explained to the NATO and EU foreign ministers over dinner that the US did not violate the rights of terrorist suspects and Mr De Hoop Scheffer said he did not expect the discussion to continue at NATO.

Complaints that the US has overstepped its bounds and may have practised or condoned torture have dogged Ms Rice throughout a four-nation tour of Europe this week.

In Washington President Bush tried to calm the uproar over allegations of secret CIA prisons, reassuring the chancellor of Austria that the US is abiding by laws forbidding torture.

Ms Rice has refused to answer directly whether the US keeps terrorist suspects in detention centres that violate European legal and human rights guarantees. She assured German Chancellor Angela Merkel on Tuesday that the US would work to rectify any mistakes it has made in its war on terror.

Before Ms Rice arrived in Brussels, the Council of Europe said human rights campaigners had been granted permission to look at images in the archives of the EU's main satellite centre, as well as log books held by its air safety organisation, to investigate claims about CIA flights and prison facilities.