BAGHDAD, Oct 22: A top US general said on Wednesday groups linked to the Al Qaeda network might be behind major bombings in Iraq, although no confirmed members of Osama bin Laden’s network had been caught.

Guerillas kept up attacks on US forces and an oil ministry source acknowledged this week’s pipeline explosion was the most destructive carried out by saboteurs to date.

Violence and sabotage hampering reconstruction efforts provide a sobering backdrop to an international donors’ conference on Iraq that starts in Madrid on Thursday.

Lt Gen Ricardo Sanchez, commander of US ground forces in Iraq, said Al Qaeda-linked groups, including Ansar al Islam, were operating in Iraq.

“We believe that some of the operations that have been conducted recently...in terms of bombings are linked to those organizations,” Gen Sanchez said at a news conference.

He said US forces had seized members of Ansar al Islam, which used to have bases in northern Iraq, and other groups.

“We know there are organizations that have links back to Al Qaeda. We do not have any confirmed Al Qaeda operatives actually in custody at this point,” Gen Sanchez said.

The United States said before the invasion that Al Qaeda had links with Baghdad, but it has not substantiated the charge.

Bombers have targeted the Jordanian and Turkish embassies, U.N. headquarters, a hotel used by Iraqi politicians, and a police station in recent months.

GUERILLA ATTACKS: A roadside bomb wrecked a US military vehicle in the flashpoint town of Falluja, west of the capital, on Wednesday but the military could not say if there had been US casualties.