SAMARRA, Iraq — Suicide bombers dressed as members of the Iraqi security forces killed seven people and wounded 12 in an attack on a power plant north of Baghdad on Saturday, officials and a survivor said.

Wearing military uniforms and armed with grenades, the three attackers entered the facility in Samarra, about 100 km north of the capital, said Gen. Qassem Al-Tamimi, head of a police unit in charge of protecting the vital installations.

A police officer, who spoke on condition of anonymity, said one of the bombers detonated his explosives belt while the two others were shot dead by security reinforcements who rushed to the scene.

He said seven people were killed and 12 wounded in the attack.

"At 2:00 am we were woken up by shots being fired," Abdel Salam Ahmed, one of the employees who was hit by gunfire in the legs, told AFP from his hospital bed.

He recalled running with colleagues away from the shooting.

"We ran into one of them (the militants). Some of us hid while two others kept running toward the exit, shouting 'we are employees' but they (the attackers) shot them dead," he said.

Prefabricated houses where employees were sleeping were destroyed as explosions rang out in the power plant, an AFP reporter said.

Several tanker trucks were also damaged and the remains of one of the suicide bombers lay on the ground, the reporter said.

The police official said security reinforcements evacuated the employees.

The attack comes as Iraqi Shiites mark the first day of the Eid Al-Adha feast.

There was no immediate claim of responsibility for the attack, but Daesh (the so-called IS) militant group frequently carries out suicide bombings in Iraq.

In 2014, Daesh captured almost a third of Iraqi territory in a lightning offensive. It now only holds two pockets of territory in the country. — AFP