Pakistani security forces have fired into the air and lobbed tear gas in Islamabad, where protesters are holding an early morning march and calling on the country's political leaders to resign and dissolve the government.
The demonstrators gathered on one of the city's main thoroughfares for an anti-corruption protest. They were acting at the urging of populist Pakistani cleric Tahir-ul Qadri. He told the tens of thousands of people at the protest to march on parliament.
Qadri's supporters pushed aside barriers of barbed wire and shipping containers that police had erected to contain the crowd.
Qadri said he would speak to his supporters around mid-day outside parliament to 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 immediately, 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.