First demand of the ''Azadi March'' protesters was the resignation of Imran Khan (File Photo)

Pakistan's hard-line cleric Maulana Fazlur Rehman on Friday gave Prime Minister Imran Khan a two-day ultimatum to resign, saying the "Gorbachev of Pakistan" must step down without testing the patience of peaceful protestors.

Addressing a massive protest rally, dubbed "Azadi March", held in Islamabad to topple the incumbent government, Rehman said only people of Pakistan and not any "institution" had the right to govern the country.

The much-hyped rally led by the right-wing opposition leader's Jamiat Ulema-e-Islam-Fazl (JUI-F) reached its final destination Islamabad on Thursday after it set off from the Sindh province and left Lahore on Wednesday.

Along with Rehman, leaders of the Pakistan Muslim League - Nawaz (PML-N), Pakistan People''s Party (PPP), and Awami National Party (ANP) participated in the march held to topple Pakistan Tehreek-e-Insaf government led by Prime Minister Khan.

"The elections of 25 July were fraud elections. We neither accept the results nor the government that came into power after those elections...We gave this government one year but now we cannot give them any more time," he said.

He said the Khan's Pakistan Tehreek-e-Insaf (PTI) government has destroyed the economy while endangering the very existence of the country.

"The Gorbachev of Pakistan must go. We give (Khan) two days to resign, otherwise, we will decide about the future," he said.

Rehman said the protestors were peaceful but their patience should not be tested. He urged his followers to stay put and "do not move until we get his resignation".

He said the future course of action will be decided in consultation with the opposition parties and the protestors if the deadline was not met.

Rehman also urged the powerful institutions (of armed forces) to stay neutral in the situation.

"We do not want conflict with our institutions. But we also want to see them to stay neutral. We give two days to the institutions (also) to decide if they will continue to support this government. After that, we will decide what opinion we should have about them (institutions)," he said.

Rehman also attacked the government's Kashmir policy and accused it of abandoning Kashmiris. He said the government was making friendship with India by opening up the Kartarpur corridor.

"The time has come to get rid of this fake government. "We will not let Imran Khan Niazi go free until Pakistan gets rid of [the prime minister]," said PML-N president Shehbaz Sharif while addressing the huge gathering attended by tens of thousands of people here.

"We have launched a movement to get rid of the government and will take this movement to logical end," he said.

The joint opposition can stabilise the country's economy within six months if given a chance, Sharif said, adding that he has never seen a worse state of affairs in the country's 72-year history.

"If given a chance, we along with the joint opposition will fix Pakistan''s economy within six months, [otherwise] you can rename me as ''Imran Niazi''," he was quoted as saying by the Dawn newspaper.

ANP leader Mian Iftikhar Hussain said the opposition parties will not rest until the Pakistan Tehreek-e-Insaf-led government has been "sent home".

He said the first and foremost demand of the ''Azadi March'' protesters was the resignation of Prime Minister Khan.

"Our election has been stolen," he said, referring to the Tehreek-e-Insaf (PTI) government coming into power.

Addressing the demonstrators at the venue, PPP chief Bilawal Bhutto Zardari said Imran Khan was a "puppet" and the nation is not ready to bow its head before a "selected" prime minister and "those who have selected him".

"We do not accept this selected government...Everything done by the government is against the interests of the people," he said, adding that the PTI government has sold Kashmir to India which was unacceptable to the people.

He said the army was deployed inside and outside the polling stations in last year elections to facilitate Khan''s victory.

Unfazed by the protest, Prime Minister Khan, while addressing a public rally in Gilgit-Baltistan, told the protesters congregated in Islamabad that when they run out of food, more will be sent to them, but their leaders should not expect any relief from him.

"Gone are the days when one used to use Islam to gain power. This is a new Pakistan. Sit however long you want. When your food runs out, we will send more. But we will not give you an (NRO)," he said.

National Reconciliation Ordinance (NRO) was an ordinance issued in October 2007 granting pardon to politicians, political workers and bureaucrats accused of corruption, embezzlement, money laundering, murder, and terrorism.

"Who are they wishing to gain freedom from? I want the media to go there and ask people who they wish to free themselves from," Khan said, adding that all his opponents appear disjointed in their thoughts and aims.

The prime minister said the protest rally had made Pakistan's enemy happy.

"I will put all of them into jail," he said, in an apparent reference to former premier Nawaz Sharif, his brother Shehbaz, former President Asif Ali Zardari and former prime minister Shahid Khaqan Abbasi.

The government has taken elaborate security arrangements to keep calm in the capital. Main roads have been completely or partially blocked by placing shipping containers.