Rome’s Colosseum was lit up last night in celebration at the release of the Italian journalist held hostage in Iraq, Guiliana Sgrena.But Italy’s happiness quickly turned to shock and sadness when it emerged that Sgrena had been injured by American troops who fired at the car taking her to the airport. An Italian agent with her has been killed, apparently while trying to protect her. The US military in Baghdad said forces had shot at a vehicle that was speeding towards a checkpoint but that they had tried to warn it to stop. US President George W. Bush has telephoned Italian Prime Minister Silvio Berlusconi to express his regret over the death. Berlusconi had earlier summoned the American ambassador, demanding an explanation. Sgrena has had an operation to remove shrapnel from her shoulder. Two weeks ago the reporter, who was abducted while carrying out interviews on the streets of Baghdad, appeared in a video begging for help and urging foreign troops to leave Iraq. Sgrena, who was snatched on February 4, is the eighth Italian to have been taken hostage and one of two female Western journalists abducted this year. The other, France’s Florence Aubenas, is believed to be still in captivity.