Controversy Follows Rice to Brussels and NATO

NATO officials voiced confidence however that the rolling dispute would not derail plans to expand the alliance-led peacekeeping force in Afghanistan, which will be the key item on the agenda at talks on Thursday.

The CIA prison row appears all the more threatening, coming as transatlantic ties seem finally back on an even keel following a concerted diplomatic offensive by Washington following US President George W. Bush's re-election.

Both sides are keen to play down the issue, diplomats say, despite a formal request by the European Union -- whose foreign ministers will also be meeting in Brussels -- for clarification over the affair.

US does not want poisoned ties

The row centers on allegations that the CIA used European airports during the transport of Islamist militant suspects. Human rights groups claim the practice breaches the detainees' fundamental rights.

The United States is keen not to let the issue poison its revived ties with Europe, nearly three years after the Iraq war plunged transatlantic relations to a historic low.

"Clearly our hope is to make our position clear and be understood by our partners, so we can move on to the very important work ahead of us," said a US diplomat, requesting anonymity.

Rice, who started her trip to Europe on Monday in Germany, is expected in Brussels late Wednesday, for an informal dinner with her NATO and EU counterparts before a formal NATO meeting on Thursday.

Even before leaving Washington she set out the basis of her answer to the Europeans, calling on them to make "tough choices" in the fight against terrorism, while insisting that the US would never accept torture.

But she declined to respond specifically to questions about the existence of secret prisons in Europe where Islamist prisoners could be held, or the existence of secret Central Intelligence Agency flights.

A unique opportunity

Diplomats say Rice could use Wednesday evening's closed-doors dinner -- where ministers will not even be accompanied by aides -- as a "unique opportunity" to explain the US position in detail.

But Dutch Foreign Minister Ben Bot said Tuesday that Rice's comments so far "were not satisfactory," and predicted "difficult discussions" Thursday. French officials have been more cautious, "taking note" of Rice's statements.

On Thursday Rice will head for NATO for a day of regular formal talks, starting with a breakfast gathering focused on the broader Middle East, of increasing interest to the military alliance.

But the main priority of the talks will be Afghanistan, and the NATO-led International Security Assistance Force (ISAF). The ministers are expected to approve plans for expanding the force into the south of the war-scarred country next year.

NATO, which took command of ISAF in 2003, has extended the force's presence progressively from Kabul into the north and then the west this year. Eventually it is expected to cover the whole of Afghanistan.

Thursday's NATO gathering will end with bilateral meetings with NATO partners, notably central Asian states, as well as regular talks with Russia and Ukraine.

Kiev would like one day to become a member of both NATO and the EU, but ministers are expected to offer it only "cautious encouragement," with no timetable, diplomats said.