A car has exploded near a Shia mosque in Saudi Arabia’s eastern city of Dammam, killing two people, the Reuters news agency reported, citing a witness.

The witness, identified only as Ahmed, told Reuters he was with his family near the mosque when “a quick explosion” happened. He did not know the cause of the blast.

He said acquaintances at the mosque told him an attendant was killed along with a bomber when he tried to prevent him from reaching it.

The bombing comes a week after a suicide bomber detonated his explosives at a Shia mosque in the gulf kingdom’s Qatif province during Friday prayers, killing at least seven people and wounding several others.