Militants kill police officer in attack on polio vaccination centre

A police officer stands guard as a health worker administers a polio vaccine to a child in a neighbourhood of Peshawar, Pakistan (AP Photo/Mohammad Sajjad)

Militants attacked a health centre used in an ongoing anti-polio campaign in north-western Pakistan on Tuesday, triggering a shootout that left a police officer dead, local authorities said.

Three of the attackers were also killed in the exchange.