Pakistan buried the victims of a massive suicide attack Monday as the death toll from Sunday's attack climbed to 54.

No one immediately claimed responsibility for the bombing in Bajaur that killed at least five children and wounded nearly 200 people.

The attack appeared to reflect divisions between local religious groups, which have a strong presence in the district of Khyber Pakhtunkhwa province that borders Afghanistan. It targeted the Jamiat Ulema Islam-Fazl (JUI-F) party, which has ties to the Afghan and Pakistani Taliban.

At least 1,000 people, according to police, were crowded into a tent near a market for the rally ahead of fall elections.

Police said their initial investigation suggested that the Daesh group’s regional affiliate, a rival of the Taliban, could be responsible, while a Pakistan security analyst pointed to breakaway factions of the Pakistani Taliban as possible suspects.

On Monday, police recorded statements from some of the wounded at a hospital in Khar, the district's principal town.

The Daesh in Khorasan Province, which police identified as a suspect in the attack, is based in neighboring Afghanistan’s Nangarhar province and is a rival of the Afghan Taliban and al-Qaida.

Pakistani security analyst Mahmood Shah said some TTP members have been known to disobey their top leadership to carry out attacks, as have breakaway factions of the group.

Shah said such factions could have perpetrated the attack to cause "confusion, instability and unrest ahead of the elections."

On Monday, female relatives and children wailed and beat their chests at family homes as the dead were taken for funerals, following local customs. Hundreds of men followed the caskets to mosques and open areas for special funeral prayers and then into the hills for burial.

As condolences continued to pour in from across the country, dozens of people who had lesser injuries were discharged from the hospital, while the critically wounded were taken to the provincial capital of Peshawar by army helicopters. The death toll continued to rise as some critically wounded people died in hospital, physician Gul Naseeb said.

Gul Akbar, the father of an 11-year-old boy who was wounded in the attack, told The Associated Press that his entire family was in a state of shock after hearing about the bombing Sunday. He said he first went to the scene of the attack, and later found his son Taslim Khan being treated in a hospital in Khar.

"What would I have done if he had also been martyred? Five children died in this barbaric attack, and we want to know what our children did wrong," he said.