ISLAMABAD — Pakistan’s army chief strongly condemned a U.S. drone attack today that killed more than three dozen people, saying the missiles struck a peaceful meeting of tribal elders near the Afghan border.

The accusation by Gen. Ashfaq Parvez Kayani adds tension to a relationship that was already strained by the shooting deaths of two Pakistanis by a CIA contractor who was freed Wednesday following a contentious deal to pay millions in “blood money“ to the men’s families.

These conflicts make it that much harder for the U.S. to convince Pakistan to cooperate on the Afghan war by targeting Taliban militants on its territory. The militants regularly stage cross-border attacks against foreign troops.

“It is highly regrettable that a jirga (meeting) of peaceful citizens including elders of the area was carelessly and callously targeted with complete disregard to human life,” said Kayani in a written statement. “In complete violation of human rights, such acts of violence take us away from our objective of elimination of terrorism.”

Kayani’s condemnation conflicted with statements provided by Pakistani intelligence officials throughout the day saying the 38 people killed and seven wounded in the attack were militants meeting to discuss sending additional fighters into Afghanistan.