A former CIA station chief in Italy received a seven-year jail sentence on Friday for his role in the kidnapping of an Egyptian Muslim cleric in 2003.
A Milan appeals court also handed down two six-year sentences to two American officials for the same crime, the first of the so-called "extraordinary renditions" organised by the United States.
The cleric, an Egyptian imam known as Abu Omar, was snatched from a Milan street and flown to Egypt for interrogation, where he says he was tortured for seven months. He was resident in Italy at the time of the abduction.
Former Rome station chief Jeffrey Castelli and the two other defendants were tried in absentia and are unlikely to serve their sentences, but they will be unable to travel to Europe without risking arrest.
The CIA declined a request for comment.
'Deeply implicated in the rendition'
Castelli was among 26 US nationals indicted by Italian authorities for their involvement in the 2003 kidnap. The judgment overturned a previous ruling by a lower court, which acquitted the three on grounds of diplomatic immunity. Last September Italy's highest court upheld guilty verdicts on 22 CIA officers and one Air Force pilot for the kidnapping.
In that case, all of the Americans were sentenced to seven years in jail, except former CIA Milan station chief Robert Seldon Lady, who was handed a nine-year sentence.
The new ruling may boost attempts to shed light on the CIA tactics during George W. Bush's presidency, and was welcomed by human rights group Amnesty International.
"Many European governments are deeply implicated in the rendition and secret detention programme and any court attempting to find out the truth about these practices is welcomed," said Julia Hall, Amnesty's expert on counterterrorism and human rights.
In December a landmark European Court of Human Rights ruling found a German car salesman, Khaled El-Masri, was an innocent victim of torture and abuse by US authorities, and condemned the CIA "rendition" programme that seized him in Macedonia and secretly flew him to Afghanistan for interrogation.
In 2007 the European Parliament found at least 1,245 CIA flights were made into or over Europe in the four years after the September 11 attacks on the United States.