At least 50 people were killed and many others injured after an explosion in Lal Shahbaz Qalandar’s shrine in Pakistan’s Sehwan on Thursday, Dawn reported. The officials have claimed it was a suicide attack.

A Sufi ritual was being performed when the incident took place. The attacker entered the shrine and threw a grenade, which failed to explode. He then blew himself up.

The injured are being treated at several hospitals in the region. Sindh chief minister Syed Murad Ali Shah has ordered the launch of a rescue operation and a probe into the incident.

Pakistan Armed Forces Spokesperson Major General Asif Ghafoor said Army Rangers had been deployed to provide assistance to the victims.

The incident follows two deadly blasts that killed at least seven people on Wednesday. Extremist groups have targeted Pakistani Sufi shrines in the past.