Rome ? Italian authorities ordered the arrests of a former CIA station chief, an Air Force commander and two other Americans and took a top Italian spymaster into custody Wednesday as they broadened their investigation into the CIA’s alleged abduction of a radical Muslim imam.

The new warrants issued by prosecutors in Milan bring to 26 the number of Americans, most of them alleged CIA operatives, being sought in connection with the February 2003 abduction of Hassan Osama Nasr. None of the Americans named in the warrants is still in Italy or has been arrested.

The cleric, known as Abu Omar, was seized off a Milan street and taken to a prison in his native Egypt, where he has claimed he was tortured.

U.S. and Italian authorities believe Abu Omar was involved in recruiting terrorists, and Italian police have said they were planning to arrest him when the CIA intervened.

Two Italian intelligence agents were also added to the indictment – the first official acknowledgment of involvement by Italian spies in the best-documented case of a secret, controversial CIA practice known as extraordinary rendition.

Marco Mancini, the No. 2 official in Italy’s military intelligence agency, Sismi, was arrested on suspicion of collaborating in the CIA-run abduction, Italian authorities said. A second Sismi official, Gen. Gustavo Pignero, who is in poor health, was placed under house arrest.