DHAKA: A bomb targeting a polio security team in north-west Pakistan has killed six policemen and a boy, police say.

The blast occurred near a police van in a market in Charsadda district, injuring at least nine others, reports the BBC.

On Tuesday, three health workers taking part in a polio vaccination drive were killed in the southern city of Karachi.

Pakistan is one of three countries where polio remains endemic. Militants oppose the polio schemes which they see as a cover for international espionage.

Militants also accuse health workers of being part of a Western plot to sterilise Muslims.

Police say Wednesday’s bomb in Sardheri Bazaar, about 30km north of the city of Peshawar, was detonated remotely.

‘Seven people including six police personnel and a child were killed,’ senior police official Shafi Ullah told media.

The police van had been taking officers to guard polio vaccination teams in the north-west.

BDST: 1430 HRS, JAN 22, 2014