Updated

A militant group allied to Al Qaeda has claimed responsibility for the car bomb attack on a convoy in Baghdad that killed 13 people, including three General Electric Co. employees, according to an Internet statement issued in the group's name.

"Your brothers, the holy warriors, ... were able to set a successful trap that targeted the mercenaries' convoy in the center of the Iraqi capital, Baghdad," said the statement signed by the military wing of Jamaat al-Tawhid wa'l-Jihad, or the Monotheism and Jihad group.

The group is led by Abu Musab al-Zarqawi (search), a Jordanian operating in Iraq. U.S. authorities believe al-Zarqawi runs his own terrorist operation, but is allied to Usama bin Laden (search).

It was not possible to authenticate the statement, which was dated Monday and posted Tuesday on a Web site that has recently carried claims of responsibility for terror attacks in Saudi Arabia and Iraq.

U.S. officials could not confirm whether al-Zarqawi had a hand in the car bomb attack in Baghdad, but President Bush said Tuesday at a news conference in Washington that al-Zarqawi is "the person who's still killing."

On Monday, Prime Minister Iyad Allawi (search) accused al-Zarqawi of trying to disrupt the transfer of sovereignty with attacks like the convoy car-bombing. Al-Zarqawi is also accused in last month's decapitation of American Nicholas Berg (search).

Of the bombing in Baghdad on Monday, the statement said: "These operations are a clear message to the Americans that your path into Muslim countries will not be easy as you think and hope."

The statement said the group's fight is a "guerrilla war that does not rely only on military strength," but on the "psychological impact" on the enemy.

"We tell everyone that our battle with the Americans, and those traitors behind them, will not end or subside until our country is free or until the last of us dies," the statement said.