Insurgents killed a vice mayor of the southern city of Kandahar while he was praying at a mosque, an official said Tuesday, the latest brazen attack on government officials in the volatile region where troops are preparing for an assault on Taliban forces. Meanwhile, NATO said one of its convoys in Khost province, on the border with Pakistan, fired on a vehicle that ignored warnings to stop late Monday night, killing four people inside the car. It said two of those killed in the incident were later identified as “known insurgents,” although the provincial chief of police, Abdul Hakim Hesaq Zoy, said the dead were all civilians, and included a 12-year-old child. In the Kandahar slaying, assailants entered the mosque and shot Azizullah Yarmal while he and dozens of others were praying during services Monday night, said Zalmai Ayubi, spokesman for the surrounding province, also called Kandahar. The assailants escaped and no arrests were made, Ayubi said. Mosques typically provide little security, making them vulnerable to insurgent death squads. Ayubi said the assassination was among a series of killings of government workers in southern Afghanistan aimed at undermining central authority by terrorizing competent individuals into leaving their posts and punishing those who defy the insurgents. “This is the work of the enemies of Afghanistan. They don't want these honest people to serve the Afghan people and work in government institutions,” Ayubi said. He said Yarmal was not known to have any powerful enemies or to be involved in any disputes.