Prosecutors are seeking a 13-year jail term for Jeff Castelli and Nicolo Pollari, former chiefs of the CIA and the Italian intelligency agency (SISMI) respectively.

Armando Spataro, the lead prosecutor, argued that two former Italy-based CIA officials, Robert Lady and Sabrina de Sousa, should receive 12-year prison sentences.

He is also seeking 11-year terms for those believed to have been directly involved in the kidnapping.

'Brutally tortured'

Twenty-five CIA agents and a US air force colonel were tried in absentia in the case, which also involved seven Italian secret service officials.

Joanna Mariner from Human Rights Watch said the case, which opened in June 2007, "puts the war on terror on trial".

"We certainly hope that these activities cannot be hidden because of state secrets," Mariner, the director of HRW's terrorism and anti-terrorism programme, said.

Abu Omar, an imam granted political asylum in Italy, was taken from a Milan street on February 17, 2003, in an operation allegedly co-ordinated by the CIA and  SISMI.

It is alleged that he was then taken to a US air force base in northeastern Italy, then flown to the US base in Ramstein, Germany, and on to Cairo.

He was released after four years in prison without being charged, and currently resides in Egypt.

Abu Omar told Human Rights Watch in 2007 that he was "hung up like a slaughtered sheep and given electrical shocks" during his time in Egypt.

"I was brutally tortured and I could hear the screams of others who were tortured too," he told the organisation.

His suspected captors failed to take many standard precautions and had spoken openly on mobile phones, leaving investigators to suspect that the US agents had cleared their intentions with senior Italian intelligence officials.

Abu Omar's lawyer is requesting $14m in damages.

Spataro said the operation "only encourages the multiplication of terrorists".