Wednesday, July 5, 2006 Posted: 1433 GMT (2233 HKT)
Judge Enrico Manzi told CNN he also issued arrest warrants for two Italians, who are members of the Italian military intelligence service Sismi.
The warrants against the four Americans are in addition to warrants issued in December for 22 other Americans alleged to have been involved in the purported abduction.
The case revolves around the alleged kidnapping of Osama Nasr Mostafa Hassan, also known as Abu Omar, in February 2003.
At the time of his disappearance, Milan prosecutors were investigating him for alleged links to terrorism.
Prosecutors allege that a CIA team seized him, flew him to Egypt, and used torture as part of an interrogation there.
Former CIA analyst Michael Scheuer said the Italian military secret service had approved the operation, and CIA sources who refused to be named told CNN last year that the agency had briefed and sought approval from its Italian counterpart for such an abduction.
But the Italian government of former Prime Minister Silvio Berlusconi vigorously denied having authorized Hassan's kidnapping, which it called illegal.
The U.S. military official named in the warrant issued Wednesday was said to have been stationed at Aviano Air Base in Italy when the alleged abduction took place.
The warrants signed against the 22 other Americans are European-wide, meaning that the targets could be legally arrested in any other European Union member nation.
Judge Manzi said the two Italians named in Wednesday's warrants are Marco Mancini, a high-ranking official in Sismi, and Gustavo Pignero, also an official with Sismi.
The charges against them are complicity in a kidnapping with the aggravating circumstances of abuse of power, the judge said.
A statement from the Milan prosecutor's office later said the two Italians had been arrested.
If an Italian role is confirmed in the kidnapping, it would lend weight to allegations that European countries colluded with the U.S. in the secret "renditions" of terrorism suspects.
Human rights groups condemn the practice known as "extraordinary rendition," saying suspects have often been sent by the U.S. to countries that practice torture.
Washington acknowledges making secret "rendition" transfers of terror suspects between countries, but denies using torture itself or handing suspects over to countries that do so.