Damage to UN headquarters in Baghdad

Pentagon officials said a terrorist group suspected of involvement in a previous Baghdad bombing may have been behind the explosion at the U.N. headquarters in the Iraqi capital.

Pentagon officials said it is too early to know just who was responsible for the U.N. headquarters bombing. But they said an al-Qaida related terrorist group is a likely suspect.

The group is Ansar al-Islam, which was linked to a deadly car bombing earlier this month outside the Jordanian embassy in Baghdad.

Pentagon officials, speaking on condition of anonymity, said investigators from the U.S. Federal Bureau of Investigation have been in the Iraqi capital, looking into the earlier attack. The officials said the FBI team may assist in the probe of the U.N. headquarters blast.

Coalition military units have been deployed to the scene of the bombing, both to secure the area and to assist in rescue and evacuation efforts. Iraqi police officers have also been sent to the scene to assist and to investigate.

The American head of Iraq's coalition provisional authority, Paul Bremer, has voiced distress over the incident. In a statement, he suggests it was a terrorist attack but gives no details.

U.S. troops in Iraq have been routinely confiscating explosives found in raids around the country in recent weeks.

Late last month, for example, military officials reported troops in one town found plastic explosives, sticks of dynamite, detonation cord, blasting caps, and other bomb-making materials. No arrests were reported when the items were discovered and confiscated.