Four people were killed when a car exploded near a Shi'ite mosque in Dammam, Saudi Arabia, on Friday, but authorities said militants failed in their bid to hit the mosque itself.

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.

A witness identified only as Ahmed said he was with his family near the mosque when "a quick explosion" happened.

A suicide bombing on May 22 killed 21 worshippers at a Shi'ite mosque in Al-Qadeeh village in an attack claimed by Islamic State.

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.

Social media accounts showed video purporting to show the congregation inside the mosque reacting with shock and alarm to the sound of the explosion ouside the building.

Saudi security forces surrounded the area and began investigating the incident. - Reuters