Thousands of Pakistanis have converged on the capital, Islamabad, to back the call of a charismatic Sufi cleric for an indefinite delay in elections and a crackdown on government corruption and inefficiency.

Tahir-ul Qadri, who recently returned home from Canada, arrived in Islamabad early Tuesday to join the protest rally. His black, chauffeur-driven SUV was showered with rose pedals as it inched its way toward a stage on one of Islamabad's main boulevards.

The influential cleric 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 Sufi cleric has called for an interim government to root out graft and mismanagement, which he blames for chronic energy shortages, slow economic growth and the rise in crime and Taliban insurgency in Pakistan.

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.