A bomb hit a motorcade carrying Iraq’s first lady through Baghdad yesterday, while the US military said a roadside explosion killed four Marines in the deadliest attack in western Anbar province in months.

The motorcade bombing in Baghdad's Kanada district injured four of Hiro Ibrahim Ahmed's bodyguards but left her unharmed, according to the office of her husband, President Jalal Talabani.

She was headed to the city's central National Theater to attend a cultural festival when the attack occurred just before noon, said the presidential office. It was unclear if she was the target or if the bombing was random.

The four Marines were killed in Anbar province on Friday, but no other details of the incident were released.

Anbar was once a stronghold for insurgents battling against U.S. forces. But in the past year the vast desert province has largely been calmed with the rise of the Awakening Council movement Sunni fighters who now turn their guns on al-Qaida instead of U.S. forces.