Explosions shook the outskirts of Sunni city of Ramadi as two suicide car bombers attacked a market and a police checkpoint, leaving 13 dead.

The first attack targeted a public market in Ramadi, some 70 km west of Baghdad, killing 8 people. Fifteen minutes later, a second car bomb was spotted near a police checkpoint. The police killed the driver in an effort to prevent the explosion. Five people were killed during the blast, including two police officers, and 12 were badly injured, said Col. Tariq Youssef, the security supervisor of Anbar province, in an official statement.

The US military has struggled to take control of Ramadi, the capital of the insurgent stronghold of Anbar province. The attacks occurred in areas controlled by the Anbar Salvation Council, an alliance of Sunni tribes formed last year to fight against al-Qaida. The Sunni blame al-Qaida for the attack.

“They committed this crime because we have identified their hideouts and we are chasing them,� Sheik Jabbar Naif al- Dulaimi, a police officer and a member of the alliance known as the Anbar Salvation Council.

In a Web statement, the Islamic State of Iraq, an al-Qaida group, warned the Salvation Council not to join forces with the government.

“We tell every father, mother, wife or brother who does not want to lose a relative to advise them not to approach the apostates and we swear to God that we will use every possible means to strike at the infidels and the renegades,� the group said.

The Islamic State also claimed responsibility Monday for attacks that killed 34 people over the weekend, including six US military and a Russian photojournalist.