Riyadh: Unknown gunmen have opened fire at a police station in a village in eastern Saudi Arabia, wounding three policemen, the interior ministry said Tuesday.

The attack took place late Sunday in the flashpoint Awamiya village, part of the predominantly Shiite Eastern Province district of Qatif where protests erupted in 2011 in the wake of the Arab Spring.

Policemen were standing outside the police station when they came under “heavy gunfire,” the ministry said in a statement carried by SPA state news agency.

One of the three wounded men is in critical condition, it said.

A firefight in Awamiya last week killed two policemen and two Shiite activists wanted by authorities over violence when security forces tried to arrest the two men, the ministry said at the time.

In January, the US embassy in Riyadh warned its citizens against travelling to Awamiya after gunmen opened fire at the car of two German diplomats, who escaped unhurt.

Demonstrations in Eastern Province, where most of the kingdom’s two million Shiites live, erupted simultaneously with a protest movement in neighbouring Bahrain in 2011.

They took a violent turn in 2012 and clashes between police and protesters have so far killed 24 people, including at least four policemen, according to activists.

Of more than 950 people arrested since 2011 for involvement in the unrest in the province, 217 are still being held