Rival attacks by suspected Al-Qaeda militants and pro-government militiamen east of the Yemen's main southern city Aden on Wednesday killed six people, tribal sources said.
"Militiamen supporting the army attacked a public building in (the Abyan provincial capital) Zinjibar killing four Al-Qaeda militants, including a Pakistani doctor," one tribal source said.
Two of the attackers were wounded, he added.
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In a separate incident, a bomb planted by suspected Al-Qaeda militants exploded near a checkpoint in the nearby town of Loder set up by a local committee formed to assist the government in its battle against the Islamists, another tribal source said.
Two of the committee members were killed and nine wounded, the source said.
Al-Qaeda's Yemen branch has taken advantage of the weakening of central authority by nearly nine months of deadly protests against veteran President Ali Abdullah Saleh to bolster its presence in several southern provinces.
Hundreds of militants from the Al-Qaeda linked Partisans of Sharia (Islamic law) group overran Zinjibar in May, and the city and adjacent towns have since been the scene of bitter fighting with the army.