The primary target appears to be a senior Pakistani police officer who was among the dozens killed, as Senior International Correspondent John Irvine reports
At least 52 people have been killed and dozens more injured after a suspected suicide bombing in Pakistan.
The attack is one of the deadliest to hit the country in recent times and happened at a rally celebrating the birthday of Islam's Prophet Muhammad, in Mastung, Baluchistan province.
No one has claimed responsibility for the attack, but local police are working on the theory that it was carried out by a suicide bomber.
Hundreds of people had gathered for a procession to celebrate the birth anniversary of the prophet.
Muslims hold rallies and distribute free meals to people on the occasion, which is known as Mawlid an-Nabi.
TV footage and videos shared on social media showed an open area near a mosque strewn with the shoes of the dead and wounded after the bombing.
Some of the bodies had been covered with bedsheets, and residents and rescuers were seen rushing the wounded to hospitals, where a state of emergency had been declared and appeals were being issued for blood donations.
A senior police officer, Mohammad Nawaz, was among the dead, government administrator Atta Ullah said.
Friday's bombing came days after authorities asked police to remain on maximum alert, saying militants could target rallies making the birthday of Islam's prophet.
Pakistan's President, Arif Alvi, condemned the attack and asked authorities to provide all possible assistance to the wounded and the victims' families.
In a statement, caretaker Interior Minister Sarfraz Bugti denounced the bombing and expressed sorrow and grief over the loss of lives.
He said it was a "heinous act" to target people in the Mawlid an-Nabi procession.
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