An Italian journalist who had been a hostage of Iraqi militants for the past month had the vehicle she was travelling in come under U.S. fire at a checkpoint near Baghdad International Airport.

Giuliana Sgrena, a reporter for Il Manifesto, was trying to leave the country after being freed by her captors. An Italian Secret Service agent accompanying her was killed.

An excerpt from the BBC story:

Italian Prime Minister Silvio Berlusconi summoned the US ambassador demanding an explanation for what he called "such a serious incident".

The US military in Baghdad confirmed that forces shot at a vehicle and said an investigation had been launched.

"Coalition forces assigned to the Multinational Force-Iraq fired on a vehicle that was approaching a coalition checkpoint in Baghdad at a high rate of speed," it said in a statement.

"The recently freed Italian journalist Giuliana Sgrena was an occupant in the vehicle and was apparently injured," it went on, adding that details were still unclear.

'Dumbfounded'

Mr Berlusconi, a staunch supporter of the US-led invasion of Iraq, said there were "disquieting questions" that needed to be answered.

"We are petrified and dumbfounded by this fatality," he said of the death of the agent, named as Nicola Calipari.

Mr Calipari died trying to shield Ms Sgrena with his body when they came under fire, Mr Berlusconi said.