A bomb exploded next to a convoy of the deputy chairman of Senate on Friday in the violence-plagued province of Balochistan, killing at least 25 people, officials said.

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 Jamiat-e-Ulema Islam , 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.

CONDEMNATION NOTES:

Prime Minister Nawaz Sharif has condemned the attack and asked the authorities to submit a report. He has also asked to provide proper medical treatment to all victims.  

Interior Minister Chaudary Nisar has condemned the attack and demanded a report from the FC and security agencies.

Balochistan Chief Minister Nawab Sanaullah Zehri has directed concerned authorities to submit a detailed report and provide treatment to the injured at the earlier.

Chairman Senate has condemned the attack and said "these terrorists think we will bow down, but they are mistaken."

Reaction from JUI-F:

Leader of JUI-F Maulana Sami-ul-Haq while speaking to Waqt News said, "We condemn this attack but want to know who are these people and why are they attacking people. When they are caught they say foreign agencies are part of menace but why are we not able to control them? Radd ul Fasaad and Zarb-e-Azab are not fulfilling the cause. We should sit and negotiate with these people and ask them why they are targeting people and who is behind them."

Leader of JUI-F Hafiz Ahmedullah while speaking to Waqt News said, We strongly condemn the attack but want to know why is JUI-F being attacked constantly. We are told that RAW and NDS is behind these attacks but the question is who will stop them? We cant, its the duty of the government and forces who need to stop our enemies from attacking Pakistan."

Leader of JUI-F Maulana Amjad Khan said, "You have a figure of 21 people who have died in the attack but JUI-F has a list with 30 people who have been killed. We have been attacked earlier too but the point is why? Are we being punished for the event we held few days ago to promote peace, where Imam e Kaaba was invited. The government needs to get serious and resolve this matter soon. The government knows that India and Afghanistan are working against Pakistan, it is their duty that they curb them." 

JUI-F chief Maulana Fazulr Rehman has condemned the attack and said that it was not the first on the party. "A number of our companions have been martyred in this attack, but we have to continue to work for this country and Islam.”