ISLAMABAD (AP) _ The Christian aid group World Vision has suspended operations in Pakistan after attackers armed with assault rifles and a homemade bomb killed six of its Pakistani employees.

The victims staffed a World Vision office helping earthquake survivors in northwestern Pakistan.

A World Vision spokesman said the attack “was completely unexpected, unannounced and unprovoked.”

Extremists have killed other foreign aid group employees in Pakistan and accused such organizations of working against Islam.

Wednesday’s attack may have been prompted by World Vision’s religious affiliation. Islamists often target Christian groups, which they accuse of trying to convert Muslims.