A powerful bomb detonated near a mosque at an event celebrating the birthday of the Islamic Prophet Muhammad in southwestern Pakistan on Friday, killing at least 52 people and injuring nearly 70 others, authorities say.

The bombing occurred in Mastung, a district in Baluchistan province, where around 500 people had gathered for a procession to celebrate the birth anniversary of Muhammad. Muslims hold rallies and distribute free meals to people on the occasion, which is known as Mawlid an-Nabi.

This is a developing story and will be updated. The Associated Press contributed to this report.