Afghan officials say insurgents have killed nine policemen in separate attacks in the country's west and east.

In western Farah province, attacks on police checkpoints killed eight policemen.

Mohammad Naser Mehri, spokesperson for the Farah governor, said two police checkpoints came under attack overnight, one in Bala Buluk district and one near Farah city.

Mehri said 13 insurgents were also killed in the fighting, which started on Monday night and lasted till early Tuesday morning.

Separately, in eastern Kapisa province, two gunmen opened fire at the police, killing one officer.

Provincial spokesperson Qais Qaderi said both gunmen were killed and five suspects were arrested.

No one claimed responsibility for the attacks, but the Taliban have been active in Farah and have stepped up attacks on security forces across Afghanistan.