Taliban gunmen attacked a gathering of Afghan clerics in the Helmand province inside a mosque on Wednesday, killing four civilians and three police officers.
A gunfight erupted between Afghan police and two armed militants inside the mosque in Lashkar Gah, police officials said, adding that seven people wounded in the attack.
According to the local media, the head of the Ulema Council of Helmand, a top religious authority, were among those who were killed.
The Ulemma Council, the highest religious authority in Afghanistan, includes some 3,000 clerics and scholars and headed by a 150-strong National Council. It has supported the government offensive against Taliban.
Qari Yousuf Ahmadi, a Taliban spokesman, claimed responsibility for the attack.
Taliban launched their spring offensive in late April, the first offensive after the NATO's combat mission formally ended last December.