BEIJING, March 22 (Xinhuanet)-- Three police officers were killed and a fourth one critically injured in two shootings that took place at a routine traffic stop and after a massive manhunt for a man wanted for violating his parole in east Oakland Saturday.

    The Gunman was also killed in the incident, Oakland police said.

    The violence began just after 1 p.m., when two officers on motorcycles stopped a suspect's vehicle in east Oakland, Oakland police spokesman Jeff Thomason said. The driver opened fire, killing one officer on the spot and gravely wounding another, who died later.

    The gunman fled the scene on foot into a nearby neighborhood, police said, leading to an intense manhunt by dozens of Oakland police, California Highway Patrol officers and Alameda County sheriff deputies. Streets were roped off and an entire area of east Oakland closed to traffic.

    At about 3:30 p.m. officers, acting on an anonymous tip, found the suspect, who had barricaded himself in an apartment building, police said. A SWAT team entered an apartment to clear and search it when the gunman opened fire, police said. Two members of the SWAT team were killed and a third was grazed by a bullet, police said.

    Acting Oakland police Chief Howard Jordan said police returned fire, killing 26-year-old Lovelle Mixon of Oakland.

    The slain officers were identified as Sgt. Mark Dunakin, 40, who was killed at the first shooting. The two members of the SWAT team who were killed at the second location were Sgt. Ervin Romans, 43, and Sgt. Daniel Sakai, 35. Officer John Hege, 41, is in a critical condition.

    (Agencies)