ROME — Italy's prime minister on Wednesday disputed Washington's version of the events leading to the killing of an Italian intelligence agent by U.S. troops in Baghdad, saying the agent had notified the proper authorities that he was on his way to the airport after winning the release of a hostage.

The top U.S. general in Iraq said he had no indication that Italian officials gave advance notice of the route the Italians' car was taking. In a statement released after the shooting, the U.S. army's 3rd Infantry Division, which controls Baghdad, said the vehicle was speeding and refused to stop.

The statement said a U.S. patrol tried to warn a driver with hand and arm signals, by flashing white lights and firing shots in front of the car.

But in his first major address since Friday's shooting strained relations between the United States and Italy, Prime Minister Silvio Berlusconi told legislators the car carrying the intelligence agent Nicola Calipari and journalist Giuliana Sgrena was travelling at a slow speed and stopped immediately when a light was flashed.

Berlusconi said Calipari had notified an Italian liaison officer, waiting at the Baghdad airport along with an American officer, that they were on their way.

However, he added, "I'm sure that in a very short time every aspect of this will be clarified.''

The idea that Calipari was killed by friendly fire is "painful'' to accept, Berlusconi said. But he reassured legislators: "The United States has no intention of evading the truth.''

Berlusconi is a staunch supporter of U.S. President George W. Bush and the U.S.-led campaign, and has been struggling to balance his decision to keep 3,000 troops in Iraq against heavy antiwar sentiment in Italy.

His 20-minute address did not mention whether ransom was paid to win Sgrena's release. Some Italian officials have suggested a ransom was paid, but there has been no official confirmation. Foreign Minister Gianfranco Fini denied Wednesday that ransoms were paid for any Italian hostages.

"There has been no payment,'' he said, speaking during a talk show on RAI1 state television.

Berlusconi once again urged Italians in Iraq to leave.

"When Italian citizens have been victims of kidnappings, the government has always acted by following two directives: It has always rejected political blackmail, while at the same time activating all the political, diplomatic and intelligence channels to obtain the release of our nationals,'' Berlusconi said.

Calipari was shot and killed as he headed to Baghdad's airport after securing the release of Sgrena, who had been kidnapped on Feb. 4. Sgrena and another intelligence officer in the vehicle were wounded.

"The case of friendly fire is certainly the most painful to bear. It feels like an injustice beyond any sentiment. It's something unreasonable,'' Berlusconi said.

In his speech, Berlusconi also revealed that there was no fourth person in the car, as Italian authorities had said initially. Instead, the fourth man was the liaison officer waiting at the airport.

Photos aired by RAI, state TV's main evening news program, showed the light grey Toyota Corolla that Calipari and Sgrena were riding in, which is still in Iraq in the hands of the U.S. military.

The body of the car appeared to have little or no damage on its left side and front, including the lights. A few bullet holes are visible on the right side _ near the wheel and the front door.

Inside, the seats appear to be covered in glass, although the photos of the interior are grainy. A bullet hole also is evident in the back seat on the left side, where Sgrena reportedly was sitting.

U.S. officials have said American troops fired at the car's engine to stop it.

Berlusconi's address was well received and legislators followed it with a standing ovation in Calipari's honour.

The office of Italian President Carlo Azeglio Ciampi said Wednesday that Bush had sent him a letter renewing a promise for a swift and thorough investigation.

In it, Bush called the shooting a "terrible tragedy'' and expressed his solidarity, Ciampi's office said.

"In his letter, President Bush assures President Ciampi that the United States will move toward a swift and exhaustive joint investigation'' between Rome and Washington, the statement added.

The U.S.-led coalition in Iraq announced Tuesday it was ordering an investigation into the shooting, to be led by a U.S. brigadier general with Italian officials' participation. Berlusconi said he expected the joint commission to release its findings in three to four weeks.