U.S. troops opened fire Friday on a car that was reportedly speeding toward a checkpoint in Baghdad, wounding Italian journalist Giuliana Sgrena and killing an Italian intelligence agent.

Sgrena had just been released by the kidnappers who held her hostage for a month.

The agent was one of three escorting her to the Baghdad airport after her release.

The military confirmed the shootings in a brief release Friday afternoon in which officials said the incident is under investigation.

Italian Prime Minister Silvio Berlusconi says he's asking the U.S. ambassador for an explanation about the shooting.

Berlusconi says he was celebrating news of the release with the woman's editor when he got a phone call about the shooting.

“It's a shame that the joy we all felt was turned into tragedy,” he said.

“Someone must take responsibility,” Berlusconi said.

He's expected to meet with the U-S ambassador Friday night.

Berlusconi has kept troops in Iraq despite public opposition at home.

The U.S. military says coalition medical personnel are treating the former hostage.

Berlusconi says she had a minor operation on her left shoulder to remove shrapnel.

According to one television report, the agent who died threw himself in front of the woman as the shooting started.

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