The Nawaz Sharif government's offer to discuss all "constitutional" demands put forth by Khan's Pakistan Tehreek-e-Insaf and Qadri's Pakistan Awami Tehreek was rejected by the two protesting groups, which have paralysed normal life in central Islamabad by staging sit-ins.
Khan, who has set a 48-hour deadline for Sharif's resignation and declared a "civil disobedience movement" against the government, did not respond to the late night offer for talks.
The cricketer-turned-politician said there is no turning back and "nothing short of fake-mandated PM's resignation will be acceptable."
The PTI leader in a Tweet said, "But I cannot keep these workers calm forever so in the interest of Pakistan, Nawaz Sharif shd resign immediately."
The firebrand Canada-based cleric also rejected the government's proposal outright and announced the plans to expand the 'Revolution March' country-wide if his demands were not met.
Qadri's 48-hour deadline for Sharif's resignation and formatting of a national government expires at Monday midnight.
"We will protest in four capitals of the provinces so that the people there can also join our revolution," he said.
Addressing thousands of his supporters camping at Aabpara square of Islamabad, the cleric said, "Time has come for a revolution."
Qadri also praised Khan's PTI on its "revolution", claiming the PAT and the PTI movements were working towards the same end goal.
"I say Zindabad to the PTI workers...they are our brothers. I congratulate Imran on announcing a two-day deadline" the cleric said.
The government late Sunday night had announced formation of two committees, consisting of members from all major political parties, to hold talks with Khan and Qadri.
The decision to hold talks with the protest leaders came hours after Khan launched a civil disobedience movement to oust Sharif over alleged vote-rigging in the last general elections in 2013 that brought him to power.
The government was to announce the composition of two committees to hold separate talks with PTI and PAT leadership to listen to their demands and convince them to call off their sit-ins, that have paralysed life in central Islamabad.
Meanwhile, Army Chief General Raheel Sharif today met Punjab Chief Minister Shahbaz Sharif and Interior Minister Chaudhry Nisar Ali Khan in Rawalpindi, the Dawn reported.
During the meeting, it was decided that dialogue should be opened immediately with PTI and PAT to listen to their demands, the paper said.
Khan had on Sunday declared a "civil disobedience movement" against the Sharif government, saying the country's future is bleak under the rule of businessmen.
The PTI chief has appealed to the people of Pakistan to stop paying utility bills and taxes to the current government.
Khan asserted that under the rule of "these businessmen who only want to make money for themselves, Pakistan's future is bleak." His remarks were directed at Sharif, one of the country's wealthiest person and the owner of Ittefaq Group.
Khan and Qadri had separately launched protests from eastern city of Lahore on Thursday, Pakistan's Independence Day, to dislodge the 15-month old Sharif government and have been camping in the capital since Saturday with thousands of their supporters.
The anti-government protests, however, appeared to lose steam as Khan's 'Azadi March' and Qadri's 'Revolution March' were unable to muster the numbers the two leaders had hoped for.
Opposition parties also distanced themselves from Khan's call for mass civil disobedience to topple the government.
Former president Asif Ali Zardari, co-chairman of the Pakistan People's Party, the largest opposition party, said Khan's willingness to use "unconstitutional means" to pursue his goals threatened democracy.
"Democracy and nation will not be served by calls for civil disobedience nor by a stubborn refusal by any side to engage in a meaningful dialogue on political issues," Zardari said in a statement.
Meanwhile, the Supreme Court rejected the government's plea seeking to restrain protesters from moving toward the capital's 'Red Zone' area, where the Parliament, the president and the prime minister's residences and embassies are located.
"That is something for the government to handle," Chief Justice Nasirul Mulk said, while rejecting the attorney general for Pakistan's (AGP) plea to pass an order stopping the protesters from entering the high-security area.
The political instability comes at a time when Pakistan is waging a war against militants -- particularly in the restive tribal regions along its border with Afghanistan.
The Army which has already been handed over the security of capital for three months, has a history of capturing power from democratically elected governments.
In its 67-year history, Pakistan has witnessed three coups, including one against Sharif in 1999 by the then army chief General Parvez Musharraf.
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This was the best Independence Day address I have seen