A suicide attack in the Afghan city of Kunduz has killed 16 people, including 11 policemen, the city's deputy police chief says, according to BBC News.

The attacker targeted officers who had gathered to provide security for a demonstration, he said.

At least 20 civilians are reported to have been injured. Police have now closed off the site.

Last month 12 people died in Kunduz province in one of several blasts at the end of the Muslim month of Ramadan.

There is concern over the capability of Afghan forces to combat continued violence ahead of the forthcoming withdrawal of Western forces from the country.

Nato combat troops are set to withdraw by the end of 2014, although foreign soldiers will still serve alongside and train Afghans.

Currently, approximately 130,000 Nato troops are fighting insurgents in Afghanistan alongside 350,000 Afghans.

Last week, a suicide bomber killed at least 25 civilians, including the son of a district governor, in an attack on a funeral ceremony in the eastern province of Nangarhar.