BAGHDAD — Iraq’s prime minister ordered an investigation on Saturday into the killing of two civilians at the main security office in western Anbar province, where the army and Shiite and Sunni volunteers are fighting militants linked to the self-proclaimed Islamic State group. The directive is the latest effort by Haider Al-Abadi, who took office in September, to show that his administration is transparent and accountable to all sects as the government seeks to roll back IS gains in the country’s north and west. Abadi’s official Facebook page called the killing “a heinous crime ... intended to sow discord and distract (citizens) and the security forces from fighting the Daesh criminal gang,” a reference to IS. “These men were innocent. They were driving a car. They were stopped by the Hashid Shaabi, taken to the Anbar Operations Command and executed there by having their throats slit,” Sabah Karhut, Anbar provincial council chief, said. — Reuters