U.S. forces in Iraq were only partially informed about last week's Italian intelligence mission to release a hostage, which ended with a shooting on the road to Baghdad airport and the death of secret service agent Nicola Calipari (search), Italian newspapers said Friday.

While U.S. authorities were informed of the presence of Calipari and a colleague, they did not know that the mission was aimed at freeing journalist Giuliana Sgrena (search), Italian dailies La Repubblica (search) and Corriere della Sera (search) reported. Sgrena hade been kidnapped in Baghdad on Feb. 4.

Calipari's killing by American forces on March 4 shocked Italy and prompted Premier Silvio Berlusconi (search) and other top officials to demand a full explanation from Washington.

A candlelit march was to be held later Friday at Rome's Capitoline Hill in memory of Calipari.

Both newspapers cited a report by Maj. Gen. Mario Marioli, an Italian who is the coalition forces' second-in-command. The report has been given to Rome prosecutors investigating the killing.

According to the newspapers, Marioli informed U.S. officials that Calipari and the other Italian officer were there, but not that the mission was aimed at releasing Sgrena. The lack of full information was possibly due to known U.S. opposition to Italy's policy of negotiating with kidnappers, Italian media have suggested.

However, the papers had conflicting versions over how much Marioli knew: Corriere said he knew that Calipari was working to have the hostage released, La Repubblica said he didn't.

Calipari was killed when U.S. troops opened fire on a vehicle carrying him, the other intelligence officer and Sgrena, who had just been released after being held hostage for a month. Sgrena and the other man were both injured.

Italy -- which is one of the largest contributors to the U.S.-led coalition with 3,000 troops in Iraq -- has said the shooting was an "accident," but has also disputed some elements of the account given by the Americans.

Berlusconi told the Senate this week that Calipari had informed the proper authorities that he was heading to the airport with the freed hostage. He said the car was traveling slowly and stopped immediately when a light was flashed at a checkpoint, before U.S. troops fired on the car.

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 also 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 into the engine block.

In interviews published Friday, Sgrena said that no light was flashed at the vehicle and that the shots were not fired in front of the car.

"It's not true that they shot into the engine," she told Corriere della Sera, adding that the shooting came "from the right and from behind."

In a parliament speech earlier this week, Foreign Minister Gianfranco Fini said photos of the vehicle, which is still in Iraq, show that the fire "hit the right side of the car."

The U.S.-led coalition in Iraq has ordered an investigation into the shooting, to be led by a U.S. brigadier general with Italian officials' participation.

Italian SKY TG24 reported that satellite phones used by Calipari have been returned to the Rome prosecutors investigating the shooting.