A U.S. military spokesman says 19 American soldiers were among those killed in Tuesday's attack on a mess tent at a military base near the Iraqi city of Mosul.
There have been conflicting numbers on the total number killed in the aftermath of the explosion. A spokesman for Task Force Olympia says 24 people were killed and more than 60 wounded.
A spokeswoman for Halliburton said seven of the dead had worked for the company's KBR subsidiary or its contractors.
There have also been differing reports on what caused the blast, which hit as hundreds of soldiers sat down for lunch. Officials said at first that rockets or mortars had hit the camp. But the task force spokesman says it was a "single explosion" that could have come from a bomb.
It was the deadliest attack to be carried out on a U.S. base in Iraq.
President Bush's Reaction
A somber President Bush says he's sending his "heartfelt condolences" to the families of those who died in the attack on a base used by American soldiers in Mosul.
The president says "any time of year is a time of sorrow and sadness" when American soldiers' lives are lost but it is "particularly sad as we head into the Christmas season."
President Bush says America is engaged in a "vital mission for peace" and he is "confident" democracy will take hold in Iraq.
The president made his comments after visiting with wounded soldiers and their families at Walter Reed Army Medical Center in Washington. It was the seventh visit the president and the first lady have made to the hospital since the war in Iraq began.