Three US Marines have been killed in separate attacks in the Iraqi city of Fallujah.
The three soldiers were killed by small arms fire during combat operations, the US military said.
Earlier the French government confirmed that engineer Bernard Planche had been released by his captors.
Iraqi Interior Ministery and police sources said it appeared Mr Planche's captors had been trying to move him when they encountered a US-Iraqi army checkpoint near the Abu Ghraib jail, and in panic had bundled him out of their car.
Mr Planche escaped and was now with US-led coalition forces, the Interior Ministry said.
Mr Planche was kidnapped in Baghdad on 5 December. He had been working for a non-governmental organisation at a water treatment plant in the east of the city.
A little-known militant group called the Surveillance for the Sake of Iraq Brigade issued a video purporting to show him being held captive and threatened to kill him unless France ended what it termed the country's illegitimate presence in Iraq.
France has no troops in Iraq and is not taking part in any form of police training. There are some 90 French nationals in Iraq, about half of them working at the French embassy.
There have been at least 15 kidnappings of foreigners in Iraq in the past three months after a three-month lull in the middle of last year when there were no reported abductions.
At least four foreign hostages, two Canadians, a Briton and an American who were in the country on a peacemaking mission, are still being held.
