ISLAMABAD - Suspected militants armed with grenades attacked the offices of a Christian aid group helping earthquake survivors in northwestern Pakistan on Wednesday, killing six employees and wounding several others, police and the organization said.

All the victims of the assault on World Vision, a major international humanitarian group, were Pakistanis.

Extremists have killed other people working for foreign aid groups in Pakistan and issued statements saying such organizations were working against Islam. Many groups have reduced operations in the northwest or pulled out altogether.