At least 52 people were killed and more than 50 injured on Friday in a suicide attack on a religious gathering to mark the birthday of Prophet Mohammed in Pakistan’s restive Balochistan province, health officials and police said.

No group has claimed responsibility for the blast, which comes amid a surge in attacks claimed by militant groups in the west of the country, raising the stakes for security forces ahead of national elections scheduled for January next year.

“The bomber detonated himself near the vehicle of the Deputy Superintendent of Police,” Deputy Inspector General of Police Munir Ahmed told Reuters, adding that blast took place near a mosque where people were gathering for a procession to mark Mohammad’s birthday, which is a public holiday.

The Tehrik-e Taliban Pakistan, an umbrella group of various hardline Sunni Islamist groups, denied it had carried out the attack.

The casualties were being treated at hospitals in the nearby town of Mastung. Interior Minister Sarfraz Bugti called the blast was a “very heinous act”.

In July, more than 40 people were killed in a suicide bombing in northwestern Khyber Pakhtunkhwa province at a religious political party’s gathering.