Khan, whose party rules the restive Khyber-Pakhtunkhwa province and is a strong supporter of talks with the Taliban, condemned the attack but stressed the need for negotiations.
He said yesterday's attack in Dir region of Khyber-Pakhtunkhwa that killed Maj Gen Sanaullah Khan and two more soldiers was a "big blow" to consensus created at a recent conference of political parties for bringing peace.
He further said any dialogue with the militants must be held within the framework of the Constitution.
While talking to reporters here, he called for a ceasefire as a first step towards holding peace talks. He claimed enemies do not want Pakistan to hold conclusive talks with the militants.