The attack targetted worshippers in al-Anoud mosque during Friday prayers, a ministry spokesperson said, quoted by the Saudi state news agency SPA.

Security forces became suspicious of a car parked near the mosque which exploded as they walked towards it, killing four people and setting cars beside it on fire, SPA said. One of those killed is suspected of being the driver.

Residents circulated pictures of the body of a man believed to be the suicide bomber as well as pictures of large black clouds of smoke billowing over a parking lot outside the mosque.

It is the second bomb attack on a Saudi mosque in a week. On Friday, May 22, 21 people were killed as worshippers attended Friday prayers at a Shiite mosque in the eastern region of the country.