Officials in Pakistan are vowing to hunt down and arrest the masterminds behind a deadly mosque attack claimed by an Islamic State affiliate.

The assault killed 63 people and wounded nearly 200.

IS said in a statement Saturday the lone suicide bomber was from neighboring Afghanistan.

He shot two police guarding the Shiite Muslim mosque in northwest Peshawar before entering inside and exploding his device.

The attack took place as worshipers knelt in Friday prayer.

The IS affiliate, known as IS in Khorasan Province, is headquartered in eastern Afghanistan.