Armed fighters have assassinated Baghdad's deputy police chief outside his home in southern Baghdad, a police source said. Brigadier Amir Nayif and his son were shot dead as they left the family home on Monday, the source said. Nayif died 10 minutes after he was transferred to al-Yarmuk hospital, Rafi Hamdi, an Iraqi journalist told Aljazeera. Nayif's son, Lieutenant Khalid, died immediately after being hit by many bullets. Their car also crashed into a house after they had been shot, added the journalist. Witnesses said the Iraqi official was not guarded, making himself an easy target for fighters who escaped after the attack. Aljazeera also learned that US helicopters bombed different sites in the northern city of Mosul on Monday. US and Iraqi forces closed five bridges in the city. **Police station targeted*** Meanwhile, a bomber driving a police car blew himself up at a police station in southern Baghdad, killing at least three Iraqis and injuring many more, a police source said. He said the powerful blast in the Zaafaraniya area sent a column of black smoke rising into the sky. Iraq's fledgling security forces have borne the brunt of attacks by fighters who accuse them of collaborating with US-led forces in the country. In a separate incident, a number of US soldiers were killed and others injured when an explosive device hit a US military patrol in Abu Ghraib, west of Baghdad, sources told Aljazeera. Also, the US military said on Monday that a marine had been killed in action in al-Anbar province in western Iraq. **PHOTO CAPTION*** In this photo provided by the Buie family Arkansas Army National Guard Cpl. Jimmy Buie of Floral, Ark., is shown in an undated photo in Iraq. Buie and two other Arkansas soldiers were killed Tuesday, Jan. 4, 2005, after their humvee was hit by a roadside bomb in the al-Shaab district of Baghdad. (AP)