Updated

Saudi Arabia says two security officers have been shot and killed in the kingdom's predominantly Shiite east.

The Interior Ministry said on Tuesday that the two officers were shot dead in Dammam amid heavy fog.

The ministry says it has launched an investigation into the shooting. It didn't name any suspects in its brief statement, which was carried by the state-run Saudi Press Agency.

Saudi Arabia's Eastern Province has seen low-level unrest since the January execution of Shiite cleric Nimr al-Nimr. There has been a series of shootings there in the time since then.

A local affiliate of the extremist Islamic State group also has carried out attacks in the kingdom in recent months.