ROME - Italy's foreign minister said today that the car carrying an intelligence officer killed by U.S. fire in Iraq last week was not speeding up and did not receive signals to stop, countering suggestions by American authorities.

Foreign Minister Gianfranco Fini, speaking to parliament, also ruled out suggestions that the shooting that killed Nicola Calipari was the result of an ambush, but reiterated the government's demands for a full explanation from Washington.

Fini was the first Italian official to openly dispute the U.S. account, and his comments put fresh pressure on Washington to get to the bottom of the matter. President Bush has promised a full investigation.

Calipari, 50, was shot Friday as he headed to the Baghdad airport after securing the release of Giuliana Sgrena a month after the Italian journalist was abducted by Iraqi gunmen.

"The car was traveling at a velocity that couldn't have been more than 40 kilometers (25 miles) per hour," Fini said. There were no attempts to stop the car, as indicated by the U.S. military, he added.

Sgrena has said the shooting might have been intentional because the United States opposes Italy's policy of negotiating with kidnappers. Fini dismissed that hypothesis as "groundless."

"It was an accident," he told lawmakers. "This does not prevent, in fact it makes it a duty for the government to demand that light be shed on the murky issues, that responsibilities be pinpointed, and, where found, that the culprits be punished."

He said Calipari, an experienced officer who had negotiated the release of other hostages in Iraq in the past, "made all the necessary contacts with the U.S. authorities," both with those in charge of airport security and with the forces patrolling areas next to the airport.

Several Rome newspapers have said a lack of communication between Italian intelligence and U.S. forces may have led to the gunfire. La Repubblica daily, citing unnamed U.S. military sources, said that Italian officials did not send notice of the hostage's liberation or of the type of vehicle she was being carried in.

Fini stressed that the U.S. government is an allied country that has promised full cooperation.

Fini's comments come a day after Italy honored the slain intelligence agent with a state funeral that drew up to 20,000 mourners. Crowds lined the streets and clapped as a car bearing his casket approached the Rome basilica.

The slaying of Calipari has fueled anti-American sentiment in a country where many protested the war in Iraq.

Premier Silvio Berlusconi, a strong U.S. ally who sent 3,000 troops to secure postwar Iraq despite opposition at home, has demanded a full explanation from Washington.

Sgrena has said Calipari died in her arms after trying to shield her with his body from the American fire.

Italian military officials said two other intelligence agents were wounded in the shooting; U.S. officials said it was only one. Sgrena rejected the U.S. military's account of the shooting, claiming that American soldiers gave no warning before they opened fire.