Five European countries have not given information about allegations of covert CIA prison transport flights, Europe's human rights watchdog has said.
The planes allegedly used by the CIA have been identified
Belgium, Bosnia-Hercegovina, Italy, San Marino and Georgia were all in breach of European human rights law, according to the Council of Europe.
The head of the council had asked all 46 members to detail any involvement.
A recent council inquiry said the CIA flew more than 100 terror suspects through Europe, possibly for torture.
In a series of questions distributed in November 2005, Council of Europe Secretary-General Terry Davis asked member states to detail what measures they had taken to ensure that people were not subject to "forced disappearances, secret detentions and extraordinary renditions".
The deadline for responses expired on Tuesday.
Mr Davis said: "I remind all five countries that their failure to reply is a clear breach of the Convention, which underpins the defence of human rights across the continent."
The breach should be rectified "as a matter of urgency", he added.
Human rights 'vital'
Membership of the Council of Europe compels member states to prevent so-called "extraordinary rendition" from taking place under their jurisdiction.
Under that remit the organisation has attempted to gather information about allegations that the CIA ran a network of secret prisons around the world, and transported suspects using European airports.
COUNCIL OF EUROPE
Founded in 1949 and based in Strasbourg, France
Forty-six members, 21 of them from Central and Eastern Europe
Set up to defend human rights, parliamentary democracy and the rule of law
Acts as human rights watchdog for Europe
Oversees the European Court of Human Rights
Comprises a decision-making committee of ministers and 630-member parliamentary assembly
Last month a Swiss senator, Dick Marty, concluded that some 100 terror suspects had been affected by the policy.
The US dismissed his report, accusing Mr Marty of relying on hearsay and press reports.
Writing in the UK's Guardian newspaper on Wednesday, Terry Davis said the global fight against terror must be underpinned by respect for human rights.
"It is our challenge, but also our firm belief that the fight against terrorism can only be credible if it respects human rights and fundamental freedoms. This is not an easy challenge," he wrote.