A cleric who has fired up Pakistanis angry at perceived government corruption and indifference demanded the country's political leaders resign in a speech to thousands of his supporters gathered in the capital.
The dramatic entry into Pakistani politics of Tahir-ul-Qadri, a preacher who until recently lived in Canada, has sparked concern from some that he is seeking to derail elections at the behest of the powerful army. Polls are expected this spring.
Mr Qadri has denied that and insisted his vague demands for election reform are simply meant to root out corruption in the political system. He pledged several weeks ago to lead a "million-man march" on Islamabad to press his demands.
During a 40-minute speech delivered behind bullet-proof glass, Mr Qadri told his supporters that the government's mandate was finished. "I give you time until tomorrow to dissolve national and all four provincial assemblies, otherwise the nation will dissolve them on their own," he said. He vowed to address his followers again in front of the parliament building.
Mr Qadri called on the demonstrators to break through the containers blocking them from the government offices and peacefully march towards the protected enclave that is often called the "red zone" in Islamabad.
Following his cry, some of the marchers pushed aside shipping containers that had been placed on the street to block them and walked towards the enclave. There, another row of shipping containers and a heavy police presence blocked them from going any further and the protesters appeared to stop. The protest has been largely peaceful since demonstrators set off from Lahore on Sunday, but the underlying tension was evident on Tuesday morning when police and protesters clashed hours after Mr Qadri's speech ended. Each side blamed the other.
Mr Qadri estimated the crowd assembled on the main avenue leading to the government centre at four million but far fewer actually attended. One city official put the number of protesters at roughly 30,000. Many in the crowd waved green and white Pakistani flags and wore buttons emblazoned with the cleric's picture.
Mr Qadri has called for vaguely worded reforms to the electoral system such as making sure candidates for office are free of corruption. His words have inspired many Pakistanis who are frustrated with a government that they say has given them nothing but unemployment, electricity blackouts and terror attacks as its five-year term comes to an end.
Security was heavy throughout the city although the rally appeared to be largely peaceful. Thousands of police in riot gear protected the streets, and mobile phones were jammed after the government warned that militants were planning to attack the protesters.
Mr Qadri returned to Pakistan in December after years in Canada, where he is also a citizen. He heads a religious network in Lahore and gained some international prominence by writing a 2010 fatwa, or religious opinion, condemning terrorism. But he was never a national political figure until this winter, when his calls for reforms ahead of elections galvanised many Pakistanis disenchanted by the existing parties.