Six women and a man, working for a health and education charity, have been shot dead in a drive-by shooting after they left a community centre in northwest Pakistan, police say.

The victims of Tuesday's attack were all Pakistanis attached to the community centre in a Swabi village.

The incident occured close to a junction for the highway which connects the northwestern city of Peshawar to the capital Islamabad and the eastern city of Lahore.

Swabi district police chief Abdul Rashid Khan confirmed the seven deaths.

"They were on their way back home when unknown gunmen on a motorcycle opened fire on their vehicle," he told the AFP news agency. "Six women and a man have died.

"The driver is injured. We are investigating the motives of the attack."

At least five of the women were teachers.

Last month, six women working to vaccinate children against polio were killed in co-ordinated attacks in Karachi and Peshawar.

Health officials said the team had received telephone calls warning them that they would regret helping the "infidel" campaign against polio.