The claim of responsibility was posted on Daesh-affiliated Aaamaq news agency hours after a bombing targeting the convoy of the deputy chairman of the senate in Mastung district of the southwestern Balochistan province..
"The death toll in today’s [Friday] blast has jumped to 26 as another injured succumbed to his wounds at the hospital," Balochistan government spokesman Anwaar-ul-Haq Kakar said.
According to the district police chief , Mohammad Gahzanfar, the bomber blew himself up near the convoy of Maulana Haideri who was on his way to Quetta after attending a graduation ceremony at a women's seminary in Mastung, located some 60 kilometers (37 miles) from the provincial capital.
Kakar told reporters that the deputy chairman Maulana Haideri’s condition was said to be stable by doctors at a military hospital police in the provincial capital Quetta.
The dead included Maulana Haideri’s driver, his personal assistant, and various security guards.
Haideri was on the phone with local Dunya TV when he was being taken to the hospital.
"It was a huge blast. My wounds are bleeding. Dozens of people have been injured. There are also reports of deaths," said Haideri who is also the secretary general of Jamiat Ulema-e Islam, one of the country's main Islamic parties.
Footage broadcast on Dunya TV showed injured being transported to hospitals, and several vehicles lying damaged in the middle of the road.
The police chief said that several critically injured had been transported to Quetta for treatment.
Prime Minister Nawaz Sharif condemned the terrorist attack vowing that such cowardly attacks could not deter his country’s resolve and efforts against terrorism.
In a statement from prime minister's office, Sharif who later left for China on a six-day-long state visit, said the perpetrators of the terrorist attack would be brought to justice.
The remote Mastung district has been beset by violence in recent years with several suicide bombings, mainly targeting the Shia pilgrims who use this route to travel to neighboring Iran.
The large Balochistan province, which is also considered to cover parts of neighboring Iran and Afghanistan, is strategically important because of the rich resources of copper, zinc and natural gas but has been riddled with violence for over six decades, with separatists claiming that it was forcibly incorporated into Pakistan at the end of the British rule in 1947.
The province, especially its capital Quetta, has also been facing a deadly wave of sectarian violence for the past decade. Over 2,000 people -- mostly Shia -- have been killed in targeted attacks and suicide bombings in Quetta and other parts of the province in the last ten years.