The trial began in Rome on Tuesday of a United States soldier, who is accused of murdering an Italian secret agent in a controversial "friendly fire" incident in Iraq in 2005.

Mario Luis Lozano, who will not attend the trial, is accused of firing on an Italian car carrying Italian Military Intelligence Service officer Nicola Calipari and a released hostage to Baghdad airport late on March 4, 2005, local media reported.

Calipari died shielding hostage Giuliana Sgrena, who was slightly wounded. He became a national hero.

As the trial opened, Italian Foreign Minister Massimo D'Alema said he was speaking "for all Italian citizens" in hoping that the trial would establish who was responsible for Calipari's death.

Asked if the trial would affect relations with the United States, he said "the Americans have a different point of view and consider the episode closed" while Italy was happy that the Italian judiciary had been able to "investigate freely."

The trial was adjourned until May 14 after Sgrena's lawyer filed a request to examine a defense contention that the US Department for State was not aware it had also been cited in the case.

Earlier, Lozano's lawyer said his client would probably not recognize the jurisdiction of the court.