Hundreds of Taliban fighters have stormed and seized a key district in the Afghani Ghazni province, beheading 15 people suspected of collaborating with authorities, including women.

Islamist insurgents attacked the restive Ajrestan district, in a strategic position southwest of Kabul, in an attempt to advance towards the capital. Following a four-day battle, the militants overrun three villages, setting fire to houses and killing a total of 70 villagers.

Ajrestan, a small town surrounded by about 100 villages in a rural area, may allow the Taliban to launch attacks into nearby provinces in the east of the country. Deputy provincial police chief Asadullah Ensafi said militants beheaded 15 people, including local police officers and their family members.

Ensafi said the Taliban also detonated a car bomb in front of an encampment where 40 police were posted, according to AP.

A Taliban spokesman, Qari Yusuf Ahmad, denied that people were beheaded but admitted the killing of police officers.

Afghanistan interior ministry said additional troops will be deployed to Ajrestan to stop it from falling in the hands of insurgents.

The country's new president, Ashraf Ghani, is expected to be inaugurated after signing a deal with runner-up Abdullah Abdullah, who will have the power to nominate someone to a post similar to that of prime minister.