Pakistani religious cleric Maulana Samiul Haq arrives for a press conference in Islamabad in 2014. File picture: Anjum Naveed/AP

Islamabad - A top Pakistani cleric known as the father of the Afghan Taliban has been assassinated in a knife attack at his residence, according to his son.

Maulana Samiul Haq, 81, was attacked inside his house in the city of Rawalpindi, near the capital, Islamabad, by two knife-wielding assassins, his son Hamidul Haq said on Friday.

He was stabbed multiple times and was rushed to hospital, but succumbed to his wounds, Haq added.

Haq ran an Islamic seminary in the north-western Pakistani town of Noshera and was a teacher to most of the Afghan Taliban's leaders, including the militia's founding father, Mullah Omer, said Taliban spokesman Yousaf Shah.

Haq was known as the father of the Afghan Taliban due to the immense influence and respect he enjoyed among the leaders and cadres of the militia.

He headed a political party and was twice elected as member of the Senate, the upper house of Pakistan's parliament.

The motive behind the killing was not immediately known, police official Zubair Ahmed said.