As part of his 'peace march', Mr Khan's motorcade of hundreds of vehicles carrying activists of his Pakistan Tehrik-e-Insaf set off for Tank town, which adjoins the tribal belt, after an overnight halt at Dera Ismail Khan in Khyber-Pakhtunkhwa province, despite indications that they may not make it to their final destination of Kotkai.
Khyber-Pakhtunkhwa Information Minister Mian Iftikhar Hussain said the march, which began in Islamabad on Saturday, would not be allowed to proceed beyond Tank in keeping with the provincial Governor Masood Kausar's instructions.
The Governor is the federal government's representative and the provincial government is bound to act on his instructions, Mr Hussain said.
He made it clear that the authorities had not barred the rally from entering the province.
The Pakistani Taliban has dismissed reports that it was ready to provide security to the march, saying it had not made any such offer.
Mr Khan on Saturday claimed that there was no threat to his march from the Taliban and only the government was trying to stop it.
Earlier on Sunday morning, authorities removed road blocks on the highway to Tank and dozens of cars joined the motorcade.
Addressing people participating in the march, Mr Khan said his party had succeeded in its mission of raising international awareness about drones.
"We have succeeded in our mission. The whole world has heard your voice and the international media has condemned drone attacks," he said.
Mr Khan claimed the government had failed to tell the international community about the Pakistani people's opposition to the drone campaign.