In its Sunday editions, The Washington Post said the CIA usually detains suspected terrorists on European soil with the help or blessing of friendly local intelligence agencies and takes them to other countries where torture is practiced.

The paper added that authorities in Italy, Germany and Sweden were investigating whether CIA agents broke local laws by carrying out so-called rendition operations.

Legal hurdles

European authorities investigating the practice face many practical and legal hurdles to filing criminal charges against US agents, including the question of whether they are protected by diplomatic immunity and the matter of determining their identity.

But prosecutors in Italy and Germany have not ruled out
criminal charges, the newspaper reported.

The CIA has kept details of rendition cases a closely guarded secret, but has defended the controversial practice as an effective and legal way to prevent terrorism, the newspaper said.

The Bush administration has received backing for renditions from governments that have been criticised for their human-rights records, including Egypt, Jordan and Pakistan,
where many subjects are taken for interrogation.