Meanwhile, an autopsy performed on the agent who died trying to save Giuliana Sgrena reportedly showed he was struck in the temple by a single round and died instantly as the car carrying Sgrena sped to the Baghdad airport.
Friday's shooting that wounded the 56-year-old journalist and killed Italian intelligence officer Nicola Calipari as they were celebrating her freedom has fueled anti-American sentiment in a country where people are deeply opposed to U.S. policy in Iraq.
Even after the full inquiry promised by Washington, many won't believe any version but their own, which is being summed up in a single word, "murder," reports CBS News Correspondent Allen Pizzey.
But government officials indicated the shootings would not affect the decision by Italian Premier Silvio Berlusconi — a strong U.S. ally — to maintain 3,000 troops in Iraq to help secure peace in the country.
"The military mission must carry on because it consolidates democracy and liberty in Iraq," Communications Minister Maurizio Gasparri was quoted as saying by the ANSA news agency. "On the other hand, we must control — but not block — the presence of civilians and journalists, who must observe rules and behavior to reduce the risks."
Sgrena, who works for the communist daily Il Manifesto, did not rule out that she was targeted, saying the United States likely disapproved of Italy's methods to secure her release, although she did not elaborate.
"The fact that the Americans don't want negotiations to free the hostages is known," Sgrena told Sky TG24 television by telephone, her voice hoarse and shaky. "The fact that they do everything to prevent the adoption of this practice to save the lives of people held hostages, everybody knows that. So I don't see why I should rule out that I could have been the target."
Italian officials have not provided details about the negotiations leading to Sgrena's release Friday after a month in captivity, but Agriculture Minister Giovanni Alemanno was quoted as saying it was "very likely" a ransom was paid. U.S. officials object to ransoms, saying it encourages further kidnappings.
White House counselor Dan Bartlett said Sunday the shootings were a "horrific accident" and pointed out that President Bush had called Berlusconi to offer condolences and promise a full investigation.
"As you know, in a situation where there is a live combat zone, particularly this road to the airport, has been a notorious area for car bombs, that people are making split-second decisions, and it's critically important that we get the facts before we make judgments," Bartlett said in a broadcast interview.
In a city where mobile phones often don't work, and different coalition radio systems don't interconnect, the U.S. troops guarding the airport road say they did not know the Italian car was coming, reports CBS News Correspondent Kimberly Dozier.
The U.S. military has said the car Sgrena was riding in was speeding, and Americans used hand and arm signals, flashing white lights and warning shots to get it to stop at the roadblock.
But in an interview with Italian La 7 TV, Sgrena said, "There was no bright light, no signal." She also said the car was traveling at "regular speed."
Sgrena also recalled how Calipari, who led negotiations for her release, died after throwing himself over her when the shooting broke out as they were celebrating her freedom on the way to the airport.
"I remember only fire," she wrote in Il Manifesto, which fiercely opposed the war in Iraq. "At that point a rain of fire and bullets came at us, forever silencing the happy voices from a few minutes earlier."
Sgrena said the driver began shouting that they were Italian, then "Nicola Calipari dove on top of me to protect me and immediately, and I mean immediately, I felt his last breath as he died on me."
Suddenly, she said, she remembered her captors' words, when they warned her "to be careful because the Americans don't want you to return."
Sgrena wrote that her captors warned her as she was about to be released not to signal her presence to anyone, because "the Americans might intervene." She said her captors blindfolded her and drove her to a location where she was turned over to agents and they set off for the airport.
Calipari's body was returned to Italy late Saturday, and Berlusconi and President Carlo Azeglio Ciampi joined Calipari's wife, mother and two children at Rome's Ciampino Airport to receive it.
An autopsy was performed Sunday, and ANSA quoted doctors as saying Calipari was struck in the temple by a single round and died instantly.
The body lay in state at Rome's Vittoriano monument and a state funeral was planned for Monday. Calipari was to be awarded the gold medal of valor for his heroism.
Defense Secretary Donald H. Rumsfeld called Italy's defense minister, Antonio Martino, "to express the sorrow of the American administration, and his own personal sorrow for the death of Nicola Calipari," Italy's Defense Ministry said in a statement. The U.S. military has promised an "aggressive" investigation.
Italian military officials said two other agents were wounded, but U.S. officials said it was only one.
Iraqi politician Younadem Kana told Belgian state TV Saturday evening that he had "nonofficial" information that a $1 million ransom was paid for Sgrena's release, the Apcom news agency reported from Brussels. The report could not be confirmed.
Sgrena told Sky TG24 she had no intention of returning to Iraq. Her captors, she said, made it clear that "they do not want witnesses and we are all perceived as possible spies."
Sgrena was abducted Feb. 4 by gunmen who blocked her car outside Baghdad University. She was later shown in a video pleading for her life and demanding that all foreign troops — including Italian forces — leave Iraq.