A populist Pakistani cleric gave the country's political leaders an ultimatum to dissolve the government and resign, telling his supporters to march on parliament early Tuesday and force the issue.

Tahir-ul Qadri called for action by tens of thousands of people gathered for an anti-corruption rally on one of Islamabad's main thoroughfares, following a 38-hour protest march from the eastern city of Lahore.

Qadri's supporters said they would heed his call. They pushed aside barriers of barbed wire and shipping containers that police had erected to contain the crowd, and set out for parliament.

The influential cleric, known as a political moderate, said he would speak to his supporters before noon Tuesday outside parliament (at six hours UTC / 0200 EST), and press his demand for the government's abdication.

Pakistan is due to hold parliamentary elections in mid-May, and parliament would be dissolved about two months beforehand. But Qadri said the government should step down immdiately, to clear the way for an interim Cabinet to root out graft and mismanagement, which he blames for chronic energy shortages, slow economic growth and a rise in crime and Taliban insurgency.

Qadri's black, chauffeur-driven SUV was showered with rose pedals by supporters as he arrived at the protest rally.

The Sufi cleric, who runs an educational and religious organization with global reach, recently returned to Pakistan after years living in Canada, where he also has citizenship.

Qadri had promised to bring a million demonstrators to the streets of Islamabad, but turnout appeared to fall far short of that goal. Pakistan's interior minister estimated Monday evening that the total crowd would not exceed 25,000.

Still, Qadri was greeted by raucous cheers from supporters as he arrived.

The protest comes just after a three-day demonstration by Hazara Shi'ites in Quetta, capital of southwestern Baluchistan province, protesting against one of the worst sectarian attacks in the country's history – bomb attacks last week that killed nearly 100 people.

After thousands of Shi'ites sat in the roads, refusing to bury their dead, the federal government yielded to the protesters' key demand and dismissed the provincial government.