Six policemen were killed and several others wounded on Sunday in a car bomb attack that targeted armoured police vehicles protecting Aden's governor and the city's security chief, police said.The bomb attack targeted the motorcade of Governor General Aidarous Zubaidi and General Shalal Shayea in Aden's neighbourhood of Mansourah, Xinhua news agency quoted a government source as saying.A source in Aden Police said the governor and the police chief escaped the terror attack unharmed but bodyguards were killed or injured.Following the suicide attack, fierce fighting broke out between Al Qaeda assailants and army units in the area.