(Adds interior ministry statement, background)

DUBAI, April 5 (Reuters) - Assailants shot dead a senior Saudi security officer west of the capital Riyadh on Tuesday, the interior ministry said in a statement carried by state media, and the attack was claimed by the militant Islamic State.

The Western-allied kingdom, the world's top oil exporter, has been hit by a spate of deadly shootings and bombings targeting security forces or its Shi'ite Muslim minority since last year, many of them claimed by Islamic State.

Saudi state news agency SPA quoted an interior ministry spokesman as saying that the officer, Colonel Kitab Majed al-Hammadi, was shot dead in the al-Arja area of al-Dawadimi province west of the Saudi capital.

The spokesman said security authorities were investigating the killing.

Islamic State's Amaq news website said the group's Saudi branch, known as the Nejd Province, carried out the attack and identified Hammadi as the director of internal security in the al-Quwayiyah region.

Islamic State views Shi'ites as heretics but is also bitterly opposed to Sunni Muslim Gulf Arab rulers and is seen to be trying to stir up sectarian strife on the Arabian Peninsula to bring about the overthrow of its ruling dynasties.

The Nejd Province group claimed responsibility on Sunday for an explosion next to a police station south of Riyadh that killed one person and damaged police vehicles.



(Reporting by Ali Abdelaty; Writing by Sami Aboudi; Editing by William Maclean/Mark Heinrich) ((Sami.Aboudi@thomsonreuters.com; +97143918301;))