Updated

The Arab satellite station Al-Jazeera (search) on Thursday reported it had received a statement and videotape from an Iraqi resistance group that claimed responsibility for attacks on American forces and threatened more.

It was believed to be the first such claim, and the first time a group said it had organized the increasingly bloody offensive.

The Pentagon repeatedly has said the attacks -- that have killed at least 18 American lives since May 1 when President Bush declared the major fighting over -- were not the work of any organized resistance. Six British soldiers were killed by an angry mob in the southern part of the country on Tuesday.

Thursday night the Pentagon said it had not seen the Al-Jazeera report and would have no comment.

In a news broadcast early Thursday, the Al-Jazeera announcer read from a statement by a previously unheard of group calling itself the Mujahedeen of the Victorious Sect (search). The group warned Iraqis away from "places where the American forces are deployed" and promised more "painful attacks against the occupation forces in the near future."

The station also aired a video it said it received from the group, showing parts of a Baghdad neighborhood and what the announcer said was an attack by the group against American military vehicles.

The announcer said a wing of the group called the Martyr Khattab Brigade (search) claimed responsibility for the attack shown in the video. The group's statement did not say when the operation took place or whether there were any casualties.

The station did not say how or when it received the statement and the video. Al-Jazeera officials were not immediately available for comment.

The pan-Arab station, which was often criticized by U.S. and British officials for its coverage of the war on Iraq, has also received statements and videos from Al Qaeda operatives, including its leader, Usama bin Laden.