MOSUL (AFP) - Four US soldiers were wounded and a local interpreter killed in a shooting at an Iraqi police station in the northern city of Mosul on Tuesday, the US military said. An Iraqi Interior Ministry official in Baghdad said earlier that two policemen had shot dead four US soldiers and their local interpreter at the police station in central Mosul. But the US military insisted there were no fatalities among its ranks, although one Iraqi interpreter was killed and another was among the wounded. The Iraqi official ruled out an insurgent attack, saying the assailants were known policemen from local tribes. He added that police and US forces had launched a manhunt at the policemen's homes in and around Mosul. "At approximately 2 pm (11 GMT) today there was a small arms attack on an IP (police) station in Mosul. Coalition forces and Iraqi police were conducting a meeting at the time of the attack," the military said in a statement. The Interior Ministry official, declining to be named, had told AFP: "Four US soldiers and their Iraqi interpreter were killed by two Iraqi policemen who opened fire at them in the Dawasa district of (central) Mosul and then fled." The shootings took place during a US army visit to the Mosul headquarters of the Iraqi police in charge of protecting the city's bridges and tunnels, local police said. In Washington, the defence department said four US soldiers were wounded along with the second interpreter, and the military in Baghdad later updated to four from three its report on the number of wounded. That was later confirmed by the military in Baghdad, which had said earlier that three soldiers had been hospitalised. "An investigation is ongoing to determine the cause and nature of the attack," the military said. Meanwhile, Iraqi authorities have arrested 11 Shia police officers for alleged attacks against Sunnis, including the murder of Vice-President Tareq al-Hashemi's sister, a security official said on Tuesday. The men are suspected of having killed or kidnapped a number of Sunnis at the height of the country's sectarian strife, said the official, who asked not to be named. Three policemen, helped by another Iraqi, killed Maysoon al-Hashemi and her driver while they were travelling in a west Baghdad district in April 2006, the official said. He said the four men had admitted murdering Hashemi, who headed the women's section of her brother's political movement, the Islamic Party, the country's main Sunni group.