The province, where al-Qaida-backed Sunni insurgents once held sway, has seen a rise in attacks against security forces and government officials in recent months. The incident also comes amid fears that next month's elections will stoke political violence.
The blast also wounded at least 26 people, said Dr. Khudhair Khalaf, the director of the provincial health authority.
Anbar is primarily made up of Sunnis, who enjoyed a privileged status under Saddam Hussein's Sunni-led regime. It was the site of some of the war's most intense fighting between U.S. forces and insurgents in the key cities of Ramadi and Fallujah.
The government compound in Ramadi was once the scene of daily attacks during the height of the insurgency in 2005 and 2006, with the governor hunkered down in his office protected by a platoon of U.S. Marines while insurgent mortar shells rained down.
By the end of 2006, many former insurgents began to rebel against al-Qaida, and joined forces with the U.S. military, who paid fighters to participate in pro-government Awakening Councils.
The decision by the Awakening Councils to join with U.S. forces against al-Qaida is seen as one of the key reasons for the drop in violence in Iraq and Ramadi these days has been comparatively peaceful.
Insurgent attacks continue, however, and may even be on the rise. On Dec. 30 twin bombings in Ramadi killed 23 people and badly wounded the governor.