Police officials say gunmen in two cars sprayed the checkpoint with bullets early on Thursday in the town of in Duluiayah. The town is about 75 kilometers (45 miles) north of the Iraqi capital.
The officials say the checkpoint commander was among the wounded. A medic in a nearby hospital confirmed the casualties. All officials spoke on condition of anonymity because they are not authorized to talk to the media.
Violence has ebbed in Iraq, but insurgents frequently attack security forces in an attempt to undermine the Shiite-led government.
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