Speaking at a press conference at his Lahore Zaman Park residence Tuesday evening, the cricketer-turned-politician rejected Sharif's offer to form a three-member judicial commission comprising Supreme Court judges to probe his (Khan) rigging allegations in May 2013 elections.
"We don't accept this offer now. Nawaz Sharif should have come up with such suggestion a year ago when I was demanding opening of four constituencies to verify thumb impression of the voters," he said.
Khan said: "Now nobody can stop us from reaching Islamabad to celebrate our Azadi (freedom) and if the government tried to stop us by force, I warn Nawaz Sharif that he is digging out his grave."
"In Islamabad we will demand resignation of PM Sharif and formation of a caretaker government of technocrats to hold fresh elections after carrying out accountability of those involved in the massive rigging in May 2013 elections.
Besides, the election commission should also be dissolved.
"We will stay in Islamabad as long as our demands are met," he demanded.
Khan vowed that he would not let the children of Pakistan become slave of the Sharifs.
"Our march will end badshahat (monarchy) of the Sharifs. We will not let the Sharifs to make our children slave of their children," he said.
Khan's Azadi (freedom) March will set off from Lahore on August 14.
Anti-government cleric Dr Tahirul Qadri's 'revolution march' will also leave for Islamabad on August 14.
The government has virtually sealed Lahore, Islamabad and several other districts of the country to prevent the protesters from reaching the federal capital.