At least five people were killed in the restive city of Awamiya during the week according to activists
A Saudi policeman was killed and six others wounded on Sunday in a rocket attack in the Shia-majority eastern district of Qatif, the interior ministry said.
The area has been rocked by unrest since 2011, when Shia protests erupted to demand equality in the Sunni-dominated Gulf kingdom.
Sunday's incident saw a police patrol come under a "terrorist attack with a rocket" in the Almosara neighbourhood in the city of Awamiya in Qatif, the ministry said in a statement carried by state news agency SPA.
It said the six wounded officers were hospitalised and in a stable condition.
Qatif has seen a string of assaults on security forces in recent weeks.
At least five people were killed in Awamiya during the week, activists and a family member said on Thursday, as security forces continue an operation to flush out suspected Shia militants.
Saudi interior ministry spokesmen could not immediately be reached by telephone for comment on the reports by community and political activists on social media about the violence in Awamiya.
Most of Saudi Arabia's Shia live in the oil-rich east, where they have long complained of marginalisation.
Authorities have blamed the violence on "terrorists" and drug traffickers.
Canada warned on Saturday that it was reviewing reports that Saudi Arabia is using Canadian armoured vehicles in the Awamiya crackdown.
"We are looking at these claims very seriously ... and have immediately launched a review," Prime Minister Justin Trudeau, speaking in French, said during a visit in central Canada.
The Globe and Mail reported earlier that light armoured vehicles sold by Canada to Saudi Arabia had been used against Shia civilians in a major operation that left several people dead in the town of Awamiya in Eastern Province.
Experts told the newspaper that vehicles appearing in photos and videos of the Saudi operations were Gurkha RPVs produced by Terradyne Armored Vehicles near Toronto.
Earlier, a spokesman indicated that Canada's foreign minister, Chrystia Freeland, was "deeply concerned about this situation and has asked officials to review it immediately".