Muslim cleric Sami ul-Haq, known as the "Father of the Taliban" for having taught some of the Afghan Islamist movement's leaders, was killed on Friday in a Pakistani city, a relative and his deputy said.
Haq's son, Hamidul Haq, confirmed that his father was killed on Friday.
However, other reports from Pakistan said Sami ul Haq was stabbed to death.
Media reports said that a security guard of the deceased cleric was critically wounded.
Haq was known as the father of the Afghan Taliban due to the vast influence and respect he enjoyed among the leaders and cadres of the militia. Maulana Sami was a heart patient, Hamid said.
Haq was the chief of the Darul Uloom Haqqania seminary in the northern Pakistani town of Akora Khattak, the alma matter of several senior leaders of the Afghan Taliban, including former chief Mullah Omar and Mullah Akhtar Mansour. He was twice elected as member of the Senate. Samiul Haq was also a founding member of Muttahida Majlis-e-Amal.
Samiul Haq was now the chancellor of Darul Uloom Haqqania, a Deobandi Islamic seminary which is the alma mater of many prominent Taliban members.
Pakistan Tehreek-e-Insaf (PTI) condemned the killing of Maulana Samiul Haq and said that serious action would be taken against the killers.
The news of his death comes at a sensitive time, with religio-political parties out on the streets protesting the Supreme Court's acquittal of Asia Bibi, a Christian woman, in a blasphemy case.
"The martyrdom of Maulana is a big tragedy", he said, adding that Maulana had met Prime Minister Imran Khan 15 days ago as part of government's efforts to introduce modern education in seminaries. Haq had emerged as one of Khan's allies since the PTI came to power in the province after elections in 2013.