A car bomb tore through an open-air market west of Baghdad on Tuesday, killing at least eight people, an Iraqi police official said.

It was the second consecutive day of attacks in the mostly Sunni Anbar province, raising questions about the ability of Iraqi security forces to keep the lid on violence as U.S. troops withdraw from the region.

Tuesday's blast came at sundown, when a parked car rigged with explosives went off in a popular open-air market in Fallujah, about 40 miles west of the Iraqi capital, the official said. At least 20 people were wounded.

The casualties were confirmed by a hospital official.

The explosion also destroyed nearly a dozen cars and damaged at least nine stalls selling vegetables and fruits, the official said.

Both officials spoke on condition of anonymity because they were not authorized to release the information to the media.

Fallujah was once an insurgent stronghold in the Anbar province, a vast stretch of land west of Baghdad to the Jordanian and Syrian borders. The province has been relatively stable since Sunni fighters turned against Al Qaeda in Iraq and joined forces with the U.S. military in 2006 to fight the insurgency.

But the province has been shaken in recent weeks by a series of attacks on police and Iraqi army checkpoints. Despite the dramatic decrease in violence in Iraq, insurgents routinely target Iraqi security forces across the country.

On Monday, a suicide bomber killed at least six mourners at funeral for a member of a prominent tribe with ties to both security forces and insurgents in Haditha, authorities said. At least 15 people were injured in that blast.

A week earlier, a tanker truck packed with explosives slammed into a police base near another Anbar city, Ramadi, killing at least seven people and wounding 16, authorities have said.