Ayobi said that Taliban fighters carried out the attack, although no group or individual has claimed responsibility.

In recent months, fighters linked to the Taliban and al-Qaeda have been resurgent against Afghan security forces and troops from the Nato military alliance.

On Sunday, a suicide attacker killed two Afghan civilians and wounded two German soldiers serving with Nato in the northern province of Baghlan.

Two US soldiers were injured on the same day in a bomb attack on the outskirts of the western city of Herat, the US military said.