An activist, citing witnesses, told Reuters earlier that an explosion was followed by gun attack on Imam Rida Mosque in the town of Mahasen in al-Ahsa region in the Eastern Province.
Residents said security forces were exchanging gunfire with five “terrorists”.
In August, a suicide bomber killed at least 15 people in an attack on a mosque used by members of a local security force in southwest Saudi Arabia. In May, a suicide bomber blew himself up during Friday prayers at a mosque in the village of al-Qadeeh in eastern Saudi Arabia, killing at least 21 and wounding 81 others.
