ABU DHABI, May 29 (Reuters) - A car exploded near a Shi'ite mosque in Saudi Arabia's Dammam on Friday, killing two people, a witness said.

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.

(Reporting By Sami Aboudi; Writing By Maha El Dahan; Editing by Angus MacSwan) ((Maha.Dahan@thomsonreuters.com; + 9712 4082101; Reuters Messaging: maha.dahan.thomsonreuters.com@reuters.net))

Keywords: SAUDI SECURITY/