ISLAMABAD- Thousands of protesters tried to blockade Parliament today after an anti-government cleric told them not to allow anyone in or out, with Prime Minister Nawaz Sharif inside at the time, but the lawmakers left by a back entrance.

Tahir ul Qadri and Imran Khan want Sharif to resign over allegations of corruption and election rigging. The Supreme Court summoned both to appear before the court tomorrow.

The peaceful protests have raised questions over the stability of the nuclear-armed nation of 180 million people. Its civilian government is struggling to assert its authority after decades when the country swung between democracy and military rule.

On Tuesday night, protesters used cranes and bolt cutters to dismantle police barricades and surround parliament. "Don't let all those inside come out and don't let anyone go in," Qadri told supporters.

His exhausted followers, some carrying blankets or colorful umbrellas, were resting in the shade on the grass on Constitution Avenue when he spoke. But they immediately rose to block the entrance to parliament.

Paramilitary forces in the area did not intervene and Qadri urged the crowd to remain peaceful.