deadly bombing

Police prevented the bomber from entering the building, but he blew himself up at the entrance killing himself and five other people.

Another 13 people were injured.

The officials blamed Saturday's attack on the Allied Democratic Forces (ADF), a militant group said to be linked to the so-called Islamic State (IS).

So far no group has claimed responsibility for the attack.

More than 30 people were celebrating Christmas at the In Box restaurant when the bomb went off, two witnesses told AFP news agency.

A posting on a Twitter account known to belong to the Islamic State group claims the explosion was work of a suicide bomber wearing an explosive belt.

The attack was claimed by an affiliate of the Islamic State group calling itself the Najd Province, the same group that claimed responsibility for a pair of attacks on two Shiite mosques in Saudi Arabia in recent weeks.

Mohammed al-Faili, 32, told The Associated Press that his 70 year-old father was killed in what appeared to be a bombing attack.