Jamiat-e-Ulema Islam chief Maulana Fazlur Rehman Friday said his party would hold countrywide demonstrations on Sunday to condemn today’s blast in Mastung which killed at least 25 people and injured dozens, including a Senate deputy.

“The attack was not aimed at an individual but the entire nation,” Fazl told reporters. “We should sit and negotiate with these people and ask them why they are targeting people and who is behind them,” he added.

At least 35 people were wounded in the blast near the town of Mastung, 50km (30 miles) from the provincial capital of Quetta. Television footage showed a vehicle mangled by the blast.

Senator Abdul Ghafoor Haideri, the deputy chairman of the upper house of parliament, said minutes after the explosion he believed he was the target and he had sustained minor injuries.

"There are many casualties as there were many people in the convoy," he said.

There was no immediate claim of responsibility for the attack from the many militant groups operating in Balochistan.

Haideri is a member of JUI-F, a right-wing Sunni Islamist political party that is part of Prime Minister Nawaz Sharif's coalition government.

District health official Sher Ahmed Satakzai said the death toll had risen to 25 and 10 were in critical condition in hospital.

Security in Pakistan has improved since a crackdown on militancy began in 2014, but a fresh wave of attacks that left more than 100 people dead in February has increased pressure on Sharif's government.

Mastung police official Ghazanfar Ali Shah said the convoy appeared to have been hit by a suicide bomber, adding Haideri's driver was among those killed.

The senator, who is being treated in hospital, was on his way back to Quetta after distributing graduation certificates to students who had graduated from a religious academy.

Separatist militants in Balochistan have waged a campaign against the central government for decades, demanding a greater share of the gas-rich province's resources.

Taliban and other Islamist militants also operate in the province, which shares borders with Afghanistan and Iran. A US drone strike killed Taliban leader Mullah Akhtar Mansour last year in Balochistan.

The province was rocked by a series of attacks late last year that claimed over 180 lives and raised concerns about a growing militant presence.

A judicial report released after an attack on the province's lawyers left more than 70 dead criticised security provisions in the region and called for increased clampdowns on extremists.