Khan, the chief of Pakistan Tehreek-e-Insaf party which rules the northwestern Khyber-Pakhtunkhwa province, visited the displaced people at Bannu.
"The (military) operation should be stopped so that the people who are still trapped should escape. The attacks should not be conducted in villages where women and children are present as they are currently stranded," he said.
Khan said that so far more than 3,50,000 people have been displaced and another 2,50,000 are still in North Waziristan and trying to flee.
Khan said Bannu, a city of one million people, was not prepared to deal with the expected influx of over half a million people.
More From This Section
Meanwhile, the military authorities have extended the deadline for the evacuation of civilians today.
It is for the second time that the deadline was extended which initially expired yesterday.
The World Health Organisation (WHO) in Pakistan has expressed fears that polio virus could spread to other areas as non-immunised children have moved out of North Waziristan where anti-polio vaccination was suspended in 2012 due to threats from the Taliban.
Dr Zubair Mufti, WHO's coordinator in Pakistan, said the displacement also offered an opportunity to vaccinate thousands of children who were out of reach of polio teams for more than two years.
He also said that the threat of polio expansion was also real as displaced people will mix with the host communities.
Travelling restrictions were imposed on Pakistan in May to curtail the threat of export of polio virus.