ROME - An angry opposition branded a investigation reported to have cleared U.S. soldiers of blame for killing an Italian agent in Iraq after a hostage rescue an insult to Italy on Tuesday.

In a brief statement to the Chamber of Deputies, Prime Minister Silvio Berlusconi rejected opposition calls to discuss the case in parliament, saying news stories about the purported findings of the joint probe were leaks. He insisted the investigation was not over.

"The government ... will only speak about this when all the results of the enquiry are finalized," Berlusconi said, adding his government was in contact with the U.S. administration.

Military intelligence officer Nicola Calipari died when troops at a U.S. checkpoint opened fire late on March 4 as he was driving to Baghdad airport with Italian journalist Giuliana Sgrena after obtaining her release from insurgent kidnappers.

A U.S. Army official, briefing reporters in Washington on the preliminary results of the investigation, said on Monday the soldiers had followed their rules of engagement and should therefore face no charges of dereliction of duty.

The official said Italy, a close U.S. ally in Iraq, had balked at endorsing the report. Rome disagreed with its findings on the car's speed and whether the Italians kept U.S. troops informed.

In Washington, U.S. Defense Secretary Donald Rumsfeld said the report was not complete.

"It's an investigation. It was done together, intimately. And I think that we'll just have to wait and see what they come out with," Rumsfeld told a news conference at the Pentagon.

U.S. Air Force Gen. Richard Myers, chairman of the military Joint Chiefs of Staff, said the draft report was still in hands of U.S. Army Gen. George Casey, commander of multinational forces in Iraq.

Asked whether there might be two separate reports, Myers said: "Don't know. We'll have to wait and see."

The case comes at an awkward time for Berlusconi, who faces confidence votes in the Chamber of Deputies on Wednesday and the Senate on Thursday on a new cabinet after a coalition mutiny over a heavy regional election defeat in early April.

His decision to send 3,000 Italian troops to Iraq was deeply unpopular at home and, with a general election due in 2006, he has said they will start pulling out from September.

No Accident, Says Sgrena

Opposition parties united in condemning the reported findings as an attempt to whitewash the case.

"A unilateral conclusion absolving anyone of blame that the Italian side does not accept is an insult to the truth and to the memory of Nicola Calipari and a serious act of arrogance towards Italy," one opposition lawmaker, Giuseppe Fioroni of the center-left Margherita party, said in a statement.

Sgrena, a veteran war correspondent for the communist newspaper Il Manifesto who was wounded in the shooting, called the findings "a slap in the face" and again alleged that Calipari had been killed deliberately.

"Nicola Calipari was murdered. Don't use the word 'accident'. Now we want the truth and we want to know who gave the order to open fire on that car," she told a news conference.

The report was the latest in a series of U.S. military investigations into the killing of civilians by American forces in Iraq to have found no wrongdoing.

The New York-based Committee to Protect Journalists (CPJ) called for "a thorough and credible investigation" and said Italian-U.S. disagreement on the probe was troubling.

"The failure to reach an agreement would be a missed opportunity to address the serious issue of safety for civilians- including members of the press- at U.S. checkpoints," CPJ Executive Director Ann Cooper said in a statement.