Islamabad, Pakistan - Pakistan's Punjab province is set for a day of protests, as opposition leader Imran Khan and anti-government cleric Tahir-ul-Qadri lead thousands of supporters in a march calling for the government of Prime Minister Nawaz Sharif to resign.
Marchers departed from Lahore on Thursday morning, also Pakistan's independence day, and are travelling up the main highway to the capital Islamabad, where they plan to hold a sit-in until their demands are met.
Hundreds of Pakistan Tehreek-e-Insaf (PTI) activists gathered outside Khan's Lahore residence, with hundreds more present at Qadri’s party headquarters, local television news footage showed.
The protest comes after days of escalating political tensions in Pakistan. Khan is demanding a fresh general election, alleging that Sharif’s Pakistan Muslim League-Nawaz (PML-N) party rigged the 2013 polls.
Khan's Pakistan Tehreek-e-Insaf (PTI) won 34 seats in the National Assembly in that election, compared to the PML-N's 189, and the then-incumbent Pakistan People's Party's 46.
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Cleric calling for 'revolution'
The government has come down heavily on previous anti-government protests led by Qadri, a Canada-based cleric and former member of parliament who runs a large international network of religious schools.
At least seven people were killed after an exchange of fire at a protest in Lahore on June 17. A similar clash at a protest by Qadri supporters on August 9 led to at least four deaths, and 500 arrests.
While Qadri is also demanding that Sharif's government resign, his protest call is based on a demand for "revolution".
"We only want to take the people there, in a peaceful manner. There would be a sit-in, and it will continue. They will develop a massive and populist pressure on [the government]," he told Al Jazeera ahead of the march. "We will democratically pressurise them to resign and to leave, and to let a 'national government' be formed which may take care of affairs."
First the prime minister and members of the Election Commission should step down and then a judicial commission should be formed
In a bid to defuse the situation on Tuesday night, Sharif made a rare televised national address, asking the country's Supreme Court to set up a three-member judicial commission to probe the rigging allegations.
"All the paths to reforms will pass through parliament […] In the presence of parliament, it is impossible that national decisions are made on the streets, in squares and in grounds," he said.
"No one will be permitted to take the State's system hostage and […] provoke people, in the name of religion, to kill others," a reference to allegations that Qadri had incited violence against police officers.
Khan, however, rejected the probe as being "not acceptable".
"First the prime minister and members of the Election Commission should step down and then a judicial commission should be formed," he said at a Lahore press conference following Sharif's statement, reiterating his commitment to march on the capital and continue his protest until the sitting government resigned.
Extraordinary security measures
The government's administration in Islamabad, meanwhile, has taken extraordinary measures to secure the capital, blocking off main arterial roads leading to the parliament, government buildings and foreign embassies with shipping containers and deploying thousands of police to control the protests.
Plans are also in place to block the main highways between Lahore, the country's second-largest city, and Islamabad, authorities said.
Islamabad's entry and exit points are expected to be sealed ahead of the protesters' arrival.
Mobile phone services have been shut down in certain areas of the city "to avoid any untoward incident and security threats", according to a statement from the Pakistan Telecommunications Authority.
Similar measures were also taken in parts of Lahore ahead of the march, but a court order on Wednesday directed police to remove the blockades from the city.
Follow Asad Hashim on Twitter: @AsadHashim
Imran Khan's PTI party is live-streaming the protests. Al Jazeera takes no responsibility for external content.