At least 35 persons were killed and over 200 were injured in a blast in Pakistan’s Khyber Pakhtunkhwa province on Sunday, Dawn reported.

The explosion took place at a convention of Islamist political party Jamiat Ulema Islam-Fazl in the Khar tehsil of the Bajaur district.

Maulana Ziaullah Jan, a regional leader of the party, was among those killed, Bajaur District Emergency Officer Saad Khan said.

Authorities cordoned off the area and expressed fears that the toll could rise further. Visuals on Twitter showed people carrying many of those injured to a hospital.

Over 150 injured persons were taken to the Bajaur District Headquarters Hospital, District Health Officer Faisal Kamal said. Those in critical condition were taken to the Lady Reading Hospital in Peshawar.

A witness, Rahim Shah, said that over 500 people were at the meeting when the blast took place. “We were listening to a bayan [speech] when a powerful explosion knocked me unconscious,” he said.

Shah said that when he regained consciousness, he saw blood everywhere. “People were screaming and even shots were fired,” he said, according to Dawn.

Deputy Inspector General of Police Nasir Mehmud Satti said an initial investigation suggested that it was a suicide blast, PTI reported. However, he said that evidence was being collected to determine the nature of the explosion.

Jamiat Ulema Islam-Fazl leader Hafiz Hamdullah said he was slated to attend the convention, but could not do so due to personal commitments. “I strongly condemn the blast and want to give a message to the people behind it that this is not jihad but terrorism,” he said.