Saudi forces yesterday killed five suspected militants believed to be linked to an al Qaeda attack on the world?s biggest oil processing plant, the interior ministry said.

Security sources and witnesses said earlier a shootout erupted at dawn after security forces besieged suspects in a villa in east Riyadh where several Western residential compounds are located.

An official statement said five men were killed and one other suspected militant was arrested elsewhere in the capital.

?Early this morning security forces stormed a building in east Riyadh which a criminal gang was using as a centre for attacks and corruption,? it said. ?All five were killed after an intense exchange of fire.?

The shootout took place days after al Qaeda suicide bombers tried to storm the Abqaiq oil facility in the first direct strike on a Saudi energy target since the militant group launched attacks aimed at toppling the US-allied monarchy in 2003. The kingdom is the world?s biggest oil exporter.

The men were hiding in a villa in a newly-developed residential district near the al-Hamra area where several Western housing compounds are located, security sources said.

Security sources said police had tracked down the militants after pursuing two vehicles that appeared on the surveillance video of the Abqaiq facility shortly before it was attacked.

One source said the men were also traced through Internet monitoring. An Internet statement issued at the weekend said al Qaeda was behind the Abqaiq attack.

The Saudi wing of Osama bin Laden?s network has been weakened by a government crackdown in which its leaders have either been killed or arrested.

Witnesses in Riyadh said they heard the sound of heavy gunfire and what appeared to be mortars as security forces surrounded the suburb and sealed it off before dawn.

?Around the time of dawn prayers, we heard the sound of shots and saw the sky light up. Then a short time later there were heavy explosions,? journalist Odwan al-Ahmar, who lives in the area, told Reuters. The clashes trapped about two dozen worshippers in a mosque, he said.

The shoot-out ended after two hours with the deaths of all of the men inside the building, the security sources said.

<B>Andrew Hammond </B>