PESHAWAR: Four women aid workers were gunned down Monday in a restive part of northwestern Pakistan, police said, as a fresh wave of extremist violence rattles the Afghan borderlands. The aid workers were ambushed by two gunmen as they were driving through a village in North Waziristan district, according to local police chief Shafiullah Gandapur, who said just one passenger survived the assault. "No one has claimed responsibility for the attack so far but it was surely an act of terrorism," he told AFP. Gandapur said the aid workers were affiliated with a programme run by a local institute to develop household skills for women. The incident and death toll was confirmed by Rasul Khan, another local police official.