BAGHDAD (AP) — Iraqi authorities say at least three attackers have entered a power station in Samarra and blown themselves up, killing seven workers and wounding eight security forces.

Brig. Gen. Yahya Rasool says two of the attackers disguised themselves as workers and a third wore a security forces uniform. The attack happened at dawn Saturday. No one immediately claimed responsibility for the attack.

Electricity Ministry spokesman Musaab al-Mudaris says seven employees were killed and eight security forces were wounded and he put the number of attackers at four.

Al-Mudaris says one attacker was shot and killed, while the others blew themselves up.

Samarra is 125 kilometers (78 miles) north of Baghdad.