The blast happened on the outskirts of Khar, the capital of Bajour district in Khyber Pakhtunkhwa, police said.

Nearly 200 people, including children, were also injured when the suicide bombing went off at a rally organised by supporters of hardline cleric and political party leader Maulana Fazlur Rehman.

Some of those seriously wounded were airlifted to a hospital in the provincial capital, Peshawar.

Pictures from the scene also showed people being put into ambulances and the blast area being cordoned off, with emergencies declared at local hospitals.

Local party official among dead

One of the dead is the local leader of Mr Rehman's Jamiat Ulema Islam-Fazl party, Maulana Ziaullah.

Mr Rehman himself was not in attendance at the rally, officials said.

His Islamist party is part of Pakistan's coalition government and he also leads the Pakistan Democratic Movement, which united opposition parties against the then prime minister Imran Khan.

The group formed in September 2020 in a bid to oust Mr Khan, succeeding via a no-confidence vote last year.

Sunday afternoon's event came as parties prepare for a general election later this year.

Prime Minister Shabaz Sharif condemned the attack as being "against the democratic system".

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Witnesses describe aftermath

Among the injured was 45-year-old Adam Khan, who was hit by splinters in his leg and hands.

"There was dust and smoke all around," he said.

Mohammad Wali said he was listening to a speaker address the crowd when the blast happened.

"I was near the water dispenser to fetch a glass when the bomb exploded, throwing me to the ground," he said.

"We came to the meeting with enthusiasm but ended up at the hospital seeing crying wounded people."

The death toll could rise as many of those hurt are critically injured.

Pakistan's leaders 'feeling threatened'

Pakistani journalist Zahir Shah Sherazi told Sky News the blast would give "a very negative message" to any parties holding campaign events in the coming weeks and months.

"They are feeling threatened," he said of Pakistan's leaders, who will contest the election within 60 days of the country's national assembly dissolving on 13 August.

The prime minister, Mr Sharif, said he had spoken to Mr Rehman, who has called for an inquiry into the attack.

"Those responsible will be identified and punished," Mr Sharif added.

Mr Khan, who wants to return to power, said Pakistan "cannot afford another wave of terrorism".

"Those in power must shift their focus from political engineering to director state's efforts and resources towards countering terrorism," he wrote on X (Twitter).

Area known for militant attacks

Nobody immediately claimed responsibility, but Islamic State operates just across the border in Afghanistan.

Mr Rehman is considered pro-Taliban, the group which has governed Afghanistan since summer 2021.

A Taliban spokesman offered condolences to relatives of the dead and prayed for a "speedy recovery of the injured".

Bajour was a safe haven for Islamic militants until recent years, when Pakistan's military carried out operations to eliminate the threat.

This included members of the Pakistani Taliban.

There are still occasional attacks, targeting security forces and civilians