BAGHDAD - A suicide bomber dressed in an army uniform detonated an explosives belt Thursday among Iraqi soldiers lined up for lunch at a base west of Baghdad, killing at least 16 and wounding 50, Iraqi officials said.

The attack took place at the joint base shared by Iraqi soldiers and U.S. troops in the former Sunni insurgent stronghold of Habbaniyah, about 45 miles (70 kilometers) west of Baghdad, two Iraqi officers said.

An Iraqi colonel, who spoke to The Associated Press over the phone from the base, said the bomber wore an Iraqi army uniform.

The colonel ruled out the possibility that the attacker had entered the base through checkpoints at the camp gates, where security is tight, and speculated he sneaked through gaps in the concertina wire fence surrounding the camp.

Both officers spoke on condition of anonymity because they were not supposed to release information to media.

It was unknown whether any U.S. soldiers were near the scene of the blast.

No group claimed responsibility for the attack but suicide bombings are a tactic used by al-Qaida in Iraq and some other Sunni insurgents.

Iraqi military and police forces have often been the target of insurgents.

On Friday, a suicide bomber driving a truck detonated a ton of explosives near a police headquarters in the northern city of Mosul, killing five U.S. soldiers and two Iraqi policemen, and wounding about 60 people.

It was the deadliest attack against U.S. troops in more than a year. A claim of responsibility for that blast was later posted on a militant Web site in the name of an al-Qaida front group in Iraq. It also claimed responsibility for a suicide attack Saturday that killed nine members of a U.S.-allied Sunni paramilitary force south of Baghdad.

Habbaniyah lies in Iraq's predominantly Sunni western Anbar province, which was a major al-Qaida stronghold and a focus of the insurgency in the first years after the 2003 U.S.-led invasion routed Saddam Hussein.

A service of the Associated Press(AP)