Italian prosecutors on Friday formally requested the extradition of 22 U.S. citizens believed to be CIA operatives on charges that they seized an Egyptian Islamic cleric off a Milan street in early 2003 and flew him to Cairo, where he later said he was tortured.

The prosecutors' decision places added pressure on U.S. officials to explain the Bush administration's alleged role in the abduction of Hassan Mustafa Osama Nasr, also known as Abu Omar. Italy and the United States have an extradition treaty that generally requires both countries to hand over defendants facing charges, although there are exceptions.

The prosecutors' extradition request is now before Italian Justice Minister Roberto Castelli, who has not said whether he will forward it to U.S. officials.

Castelli was in Washington this week to meet with Attorney General Alberto R. Gonzales. After returning to Rome on Thursday, Castelli said they discussed extradition cases but declined to say whether the Abu Omar case was among them, the Italian news agency ANSA reported.

Brian Roehrkasse, a Justice Department spokesman, said Friday the agency would not comment on what was discussed at the meeting.

Arrest warrants previously approved by a judge in Milan allege that 22 covert operatives from the CIA violated Italian sovereignty by kidnapping Nasr, who had been granted political asylum in Italy, and secretly flying him to Egypt.

According to the arrest warrants, the CIA handed over Nasr to Egyptian security officials in Cairo. Italian anti-terrorism police suspected Nasr of involvement in terrorist networks that were recruiting fighters to go to Iraq and had placed him under surveillance several months earlier.

They have said they were mystified by his disappearance until May 2004, when he was briefly released from prison in Egypt and telephoned his wife and others in Milan, and told them he had been abducted to Egypt and tortured in custody there. The phone conversations were recorded by Italian police, who had previously placed wiretaps on Nasr's phone in Milan as part of their terrorism investigation.

Four CIA veterans, however, have told The Washington Post that the CIA station chief in Rome briefed the Italian intelligence service on the operation before it was carried out and obtained approval for it.

Most of the alleged CIA operatives named in the warrants and extradition request appear to have used false identities, records show. Legal experts said it would be virtually impossible for the Italian government to win the extradition of suspects without confirming their true identities.

But Italian investigators believe that five of the 22 suspects used their real names. Among them: a man personally known by Italian counterterrorism officials as the chief of CIA operations in Milan, and a diplomat assigned to the U.S. Embassy in Rome.

Under the U.S.-Italian extradition treaty, the U.S. government is obliged to hand over defendants in most cases. Italian prosecutors have argued that even if some of the suspects were registered as diplomats they are not entitled to legal immunity on kidnapping charges.

If the Italian Justice Ministry does approve the extradition requests, the matter would be referred to the U.S. federal courts. U.S. officials would then be required to file a response; either agreeing to hand over the suspects or explaining why not.

Staff writer Dan Eggen in Washington contributed to this report.