BAGHDAD, Dec. 6 (Xinhua) -- Two Awakening Council group fighters were killed and two others injured on Saturday in a gunfire attack on a security checkpoint in the city of Baquba, capital of the volatile province of Diyala, a provincial police source said.

    "Unknown gunmen attacked early in the morning a security checkpoint manned by Awaking Council Fighters and policemen in theal-Wajihiyah town some 12 km northeast of the provincial capital Baquba," the source told Xinhua on condition of anonymity.

    The attack resulted in the killing of two fighters and the wounding of two others, the source said.

    Iraqi security forces immediately sealed off the main roads leading to the scene and immediately began a search operation seeking for the attackers, he added.

    The Awakening Councils involve local armed groups, especially some powerful former insurgent groups, who fight the al-Qaida network after the latter exercised indiscriminate killings against both Shiite and Sunni Muslim communities.

    Diyala, including Baquba, some 65 km northeast of Baghdad, has long been the hotbed of insurgency since the U.S.-led invasion of Iraq in 2003, despite the ongoing security crackdown in the province conducted by U.S.-backed Iraqi security forces.