QUETTA, Pakistan —The death toll from a bomb blast at a Sufi shrine in southwest Pakistan on Saturday has risen to 50 people with more than 100 wounded, officials said.

The Islamic State group later claimed responsibility for the suicide attack at the shrine of Sufi saint Shah Bilal Noorani in the southwestern province of Baluchistan.

Abdur Rasool, an official at the province’s home ministry, said rescuers were transporting the wounded to hospitals and the dead to local morgues, but were struggling in the difficult mountainous terrain, some 350 kilometers (217 miles) south of the provincial capital, Quetta.

The blast targeted worshipers as they were in the throes of their devotional “dhamal” dance, and the courtyard at the time was packed with families, women and children.