IS affiliate claims responsibility for Saudi police bombing

RIYADH, Saudi Arabia -- An allegedly new Islamic State affiliate in Saudi Arabia claimed responsibility for a suicide bombing Thursday at a mosque inside a police compound in the country's southwest that killed at least 15 people, most of them members and recruits of the kingdom's special forces.

It was the deadliest attack against Saudi security personnel in years and one that is likely to pull the kingdom deeper into the regional war with IS extremists.

The blast took place in an Interior Ministry compound in the city of Abha, the provincial capital of Asir, which lies along the border with war-torn Yemen. The troops killed were members of an elite counterterrorism force.

The attack came just weeks after the Saudi Interior Ministry announced the arrest of more than 400 suspects in an anti-terrorism sweep. In April, they announced the arrest of more than 90 suspects.

The kingdom for years had allowed thousands of Saudis to leave the country to join militant groups fighting in Iraq and Syria until the late King Abdullah last year decreed fighting abroad was illegal. At the same time, Saudi Arabia joined a U.S.-led coalition carrying out airstrikes in Syria and Iraq against the IS group.

The kingdom is leading a coalition targeting Yemen's Iran-allied Shiite rebels, who have carried out a number of cross-border attacks against Saudi military targets. It also has sheltered Yemen's exiled President Abed Rabbo Mansour Hadi, whose loyalists at home are battling Iran-backed Shiite rebels known as Houthis.

Hours after Thursday's bombing in Abha, a previously unheard of IS affiliate, which calls itself Hijaz Province of the Islamic State, claimed responsibility for the attack.

The group issued a statement saying an IS suicide bomber targeted a "monument of the apostate," referring to the special forces' compound in Abha. It called the kingdom's ruling family "tyrants" who have aligned themselves with "their Crusader masters," or Western allies.