(CNN) -- Iraqi authorities on Sunday closed all entrances into Ramadi and imposed a curfew after a series of car bombings killed at least 19 people and injured more than 80 others, according to Interior Ministry officials.
Authorities believe the coordinated attacks were carried out by al Qaeda in Iraq, a Sunni militant group.
Two of the car bombs detonated within 10 minutes of each other at Ramadi's police headquarters, killing at least eight police officers, the officials said.
Less than an hour later, a third car bomb, driven by a suicide attacker, detonated outside a hospital.
Ramadi -- which is located in the predominantly Sunni Muslim Anbar province -- is about 62 miles (100 km) west of Baghdad.
CNN's Mohammed Tawfeeq contributed to this report.
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