A residential and office building used by a Shi'ite Muslim militia group in Baghdad has collapsed, killing one person and injuring at least seven.

There were conflicting reports about what caused the incident Friday, at the building used by Badr Brigade, which is linked to the Supreme Council of the Islamic Revolution in Iraq. The council said it was a bomb attack, but a U.S. military spokesman said Iraqi police believe it was an accident caused by a structural fault.

The incident came two days after a senior official of the Shi'ite party was killed in the capital. Leaders of the group blamed loyalists of ousted Iraqi President Saddam Hussein. A party official tells VOA 70 members or supporters have been killed since the fall of Saddam.

In another development, the top U.S. civil administrator in Iraq confirmed an earlier media report that his convoy was hit by an explosion and small arms fire on December 6 - the day U.S. Defense Secretary Donald Rumsfeld visited Baghdad.

Paul Bremer told reporters in Basra Friday, that he was not hurt in the attack, which happened as he was traveling from Baghdad airport. U.S. officials said they have no evidence that Mr. Bremer was the specific target of the attack.