An Iraqi interpreter was killed and an unsepecified number US soldiers were wounded Tuesday in an attack on a police station in northern Iraq, the US military said. It was not immediately known how many US soldiers were wounded in the attack, Lt. Col. Dave Doherty, a military spokesman, said in a statement. He said a second interpreter was also wounded. Doherty said the attack occurred in Ninevah province, which includes the city of Mosul. He gave no more details, saying the investigation is ongoing to determine the cause and nature of the attack. It's the third brazen attack involving American forces in two weeks in northern Iraq. Mosul is considered one of the last strongholds of Sunni insurgents. Brig. Gen. Saeed Ahmed al-Jubouri, a spokesman for the provincial security headquarters, said two men wearing police uniforms opened fire on the Americans as they were visiting an Iraqi bridge protection force in Mosul, about 225 miles northwest of Baghdad. The suspects then fled the area in a car, al-Jubouri said.