ROME - The body of an Italian secret service agent shot by US forces in Iraq has been flown home to a hero's welcome amid mounting anger in Italy over his killing.

Agent Nicola Calipari died while shielding reporter Giuliana Sgrena, just freed after a month held hostage, from US troops who opened fire on their car near Baghdad airport.

Sgrena was wounded in the attack and flew back to Italy on Saturday for medical care. She rejected a statement by the US military that its forces had fired on the Italians because their car was speeding towards a checkpoint.

Calipari's coffin arrived at Rome's Ciampino airport at midnight on Saturday aboard a C-130 military plane. His wife, mother and daughter broke down in tears as his casket, drapped in an Italian flag, was carried out by a guard of honour.

President Carlo Azeglio Ciampi held both hands up to the coffin, standing motionless in front of the body for almost two minutes before allowing it to be placed in a hearse.

Prime Minister Silvio Berlusconi, government ministers and clergy looked on, while five of Italy's seven national television stations broadcast the return live, underscoring the huge sense of shock and disbelief in Italy over the killing.

Italy has proved one of US President George W. Bush's most fervent allies in Europe, but Calipari's death has put a strain on relations and Rome has demanded a full investigation.

The U.S. military said its forces shot at the car on Friday evening after flashing lights and firing warning shots to try to get it to stop.

Italy's minister for parliamentary relations, Carlo Giovanardi, told state television on Saturday that he did not believe the U.S. version of events.

Sgrena, a 57-year-old award-winning war reporter who was taken hostage on February 4. while conducting interviews in Baghdad, said there had been no warning from the US forces.

"We thought the danger was over after my release to the Italians but all of a sudden there was this shoot-out, we were hit by a barrage of bullets," she told RAI TV by telephone.

She was hit in the shoulder by a bullet during the assault, while Calipari, who had been instrumental in securing her release, was hit in the head as he tried to cover her.

"He leaned over me, probably to protect me, and then he slumped down, and I saw he was dead," she said.

In comments reported by ANSA news agency, Sgrena told Rome investigating magistrates during a debriefing that the car was not going fast and there had been no fixed checkpoint.

"The firing was not justified by the speed of our car," she said, adding it was travelling at a "regular" speed.

The shooting could rekindle anti-war sentiment in Italy, where public opinion opposed the US-led invasion of Iraq.

Berlusconi defied public opinion by sending 3,000 soldiers to Iraq after the US-led invasion in March 2003 and has rejected past calls to withdraw the troops.

Italy's centre-left, which hopes to unseat Berlusconi next year in elections and to weaken his standing at local government polls next month, is campaigning on a platform of withdrawing.

"All of us, all 57 million Italians were united as we waited and hoped that Giuliana Sgrena would be freed. Now we have the right to know what happened after her freedom," said centre-left leader Romano Prodi, ex-president of the European Commission.

Calipari's body will lie in state on Sunday in the Vittoriano monument in central Rome. He will receive a state funeral on Monday.