FACTBOX: Italy's CIA "kidnap" case

(Reuters) - An Italian judge said on Wednesday Prime Minister Silvio Berlusconi could be called to testify in the trial of U.S. and Italian spies accused of kidnapping a terrorism suspect in Milan in 2003.

Following are details of the case, the first criminal trial over "rendition", one of the most controversial methods used in U.S. President George W. Bush's war on terrorism.

WHO ARE THE SUSPECTS?

Being tried in absentia are 26 Americans including the former CIA station chiefs in Rome and Milan, Jeff Castelli and Robert Lady, and the head of security at the U.S. air base in Aviano in northern Italy.

Seven Italians, including Nicolo Pollari, head of the SISMI military intelligence agency, are also on trial.

WHAT ARE THE ACCUSATIONS?

That a CIA-led team seized Hassan Mustafa Osama Nasr, a Muslim cleric also known as Abu Omar, in Milan on February 17 2003, and flew him via Germany to Egypt, where Nasr says he was tortured with electric shocks, beatings, rape threats and genital abuse.

Nasr was released from jail in Egypt last year and lives in Alexandria.

WHY BERLUSCONI?

Pollari says Berlusconi is aware of classified documents that prove his innocence. Pollari's defense team has also sought testimony about state secrecy in the case from former prime minister Romano Prodi, former defense chiefs from Prodi's and Berlusconi's last governments and other officials.

WHAT DO THE UNITED STATES AND ITALY SAY ABOUT THE CASE?

Washington has not responded to the charges. It says it has transferred terrorism suspects to third countries, but denies torture or sanctioning torture by third parties. A U.S. official said last year Washington would not turn over any of the Americans even if Rome asked for their extradition -- something the Italian government has not done.

Berlusconi, who was Italy's prime minister at the time of the supposed rendition and was reelected last month, denies knowledge of any kidnap operation and has defended Italy's military spy agency of wrongdoing.

He has criticized the trial on the grounds it could hurt Italy's reputation in the international intelligence community.

Prodi's government has asked the constitutional court to annul the indictments, arguing prosecutors broke state secrecy rules when building their case.

WHAT DO THE SUSPECTS SAY?