At least 28 people have been killed and over 40 others injured in an explosion in Balochistan's Mastung district, which is around an hour's drive from the provincial capital, Quetta.

The bombing took place near a local seminary shortly after Friday prayers.

Deputy Chairman Senate Abdul Ghafoor Haideri's convoy was hit in the attack. The explosion occurred right as Haideri's convoy was exiting the seminary.

A Senate director staff, Iftikhar Mughal, was reportedly killed in the attack.

It is unclear whether the explosion was the result of an improvised explosive device (IED) or a suicide attack. Police say the attack is likely to have been a suicide bombing.

Haideri had been invited to the seminary for an investiture ceremony, DawnNews reported.

An eyewitness present at the event said the guests were leaving for a luncheon when Haideri's convoy came under attack.

The eyewitness told DawnNews that there was an explosion, followed by sustained firing. "After the air cleared, we saw bodies everywhere."

A police car was part of Haideri's security detail and police officials are among those injured in the blast, another eyewitness said.

Haideri belongs to Jamiat Ulema-i-Islam-Fazl (JUI-F).

While speaking briefly to media, he said he had suffered minor injuries but was otherwise fine.

He has been shifted to Combined Military Hospital Quetta for treatment. His condition, according to Balochistan government spokesman Anwar ul Haq Kakar, is "safe and sound".

“I am alive, Allah has saved my life. It was all very sudden. Broken pieces of the windscreen hit me. I am injured but safe. The driver and other people sitting next to me were badly injured,” Haideri said while speaking to Samaa TV.

Kakar told DawnNews that the death toll had risen to 25, whereas 42 others were wounded in the attack.

Haideri's driver, along with two other associates, succumbed to their injuries. The majority of those injured and killed were JUI-F party workers, rescue sources said.

Levies, police and Frontier Corps (FC) personnel cordoned off the site of the attack.

Some wounded have been transported to Civil Hospital Mastung, while those in critical condition are being transported to Quetta for treatment.

An emergency has been declared at Civil Hospital Mastung and more doctors have been called in, hospital sources said. Quetta hospitals have also declared an emergency.

The attack came a day after Haideri said at a press conference in Quetta that the JUI-F would form the next provincial government in alliance with political parties, including nationalist parties.

‘We have never shied away from sacrificing our lives’

Speaking to the press, Senate Chairman Raza Rabbani said that Pakistan is engaged in a “long and protracted” war against militancy, adding, “As a nation, we have never shied away from sacrificing our lives for the greater good of the country.”

Rabbani informed the media persons that he had spoken to Haideri a while ago. “Although his body is covered in bruises, his spirits are high. He is understandably upset at the loss of his associates, but he is trying to channel that sense of loss into a commitment to fighting terrorism in Pakistan.”

JUI-F chief Fazlur Rehman, who was also present at the occasion, reminded reporters of incidents in the past where he had come under attack. “We want to send a message of peace to the world. We believe these terrorists can not defeat our commitment to the values of our nation.”

“We consider these notorious elements defeated. They are not in a position where they can dictate their choices or harm Pakistan,” he maintained.

This is not the first time a JUI-F lawmaker has been targeted.

In 2014, JUI-F chief Maulana Fazlur Rehman was injured in a suicide blast outside a JUI-F rally in Quetta targeting his vehicle.

Before that, Rehman had survived two previous attempts on his life in March 2011 when he was targeted by two back-to-back suicide attacks.