Saudi Arabia says a policeman was killed and three were wounded during a raid in an eastern, predominantly Shiite town.

A statement from the Interior Ministry on Monday says the security forces searched several homes in the town of al-Awamiya on suspicion they were being "used by terrorist elements" and confiscated weapons and ammunition.

During the raid, which took place on Sunday afternoon, security forces encountered heavy gunfire and responded. Police also arrested four Saudi citizens.

The town was the site of anti-government Shiite-led protests in 2011 and is also the home of revered Shiite cleric Nimr al-Nimr, an outspoken government critic sentenced to death in 2014 for inciting sectarian strife — a charge he denied.

His Shiite supporters complain of discrimination from the kingdom's Sunni leadership.