KUNDUZ, Afghanistan, Jan. 27 (Xinhua) -- The Afghan security forces stormed a Taliban bastion in northern Kunduz province on Sunday, triggering heavy fighting, a security official said.

The official on the condition of anonymity said that the government forces attacked the bastion in Jangle Bashi area of Khan Abad district at 2:00 a.m. local time Sunday and so far four insurgents have been killed and five others arrested.

Confirming the report, Hayatullah Amiri, governor of Khan Abad district, told Xinhua that the strike had taken the Taliban fighters by surprise and the militants have suffered huge losses.

Taliban militants who are active in parts of the restive Kunduz province are yet to make comment on the offensive.