The Council of Europe's Human rights commissioner Alvaro Gil-Robles said he had been 'shocked' by conditions at the barbed wire-rimmed centre inside a US military base, which he witnessed in 2002.

The camp resembled 'a smaller version of Guantanamo', he told France's Le Monde newspaper, referring to the US centre at Guantanamo Bay, Cuba, where hundreds of terrorism suspects remain detained without trial.

Gil-Robles told the daily he had inspected the centre, located within the US military's Camp Bondsteel in Kosovo, in 2002, to investigate reports of extrajudicial arrests by NATO-led peacekeepers.

Gil-Robles said he had no evidence that Camp Bondsteel was linked to the alleged CIA operations.

'But I do believe that an explanation should be given for this base in Kosovo, as for other potentially suspect sites' in Europe, he told the paper.

Earlier this week the Council of Europe, which guarantees human rights in its 46 member states, launched an investigation into the alleged prisons.

The official leading the probe said Friday that Romania, which rights groups have labelled a likely site for one of the secret centres, was not hosting a large, Guantanamo-style jail.

Dick Marty told a press conference in Bucharest that he was 'convinced that there are no Guantanamos in Romania'.

However, he did not exclude the possibility of Romania having 'small centres with one or two detainees being kept temporarily for interrogation'.