Pakistani opposition politician Imran Khan says he will lead protests in Islamabad along with tens of thousands of his supporters until Prime Minister Nawaz Sharif steps down.
Addressing a rally in the Pakistani capital after leading protesters on a journey from the eastern city of Lahore, Khan said on August 16 he would stage a protest that will continue until Sharif leaves office.
"I will come here [again tomorrow] and I will spend nights here and I will stay here until Nawaz Sharif resigns," Khan said. "We don't accept a prime minister who won and who was appointed after rigged elections."
"Decide, Nawaz Sharif! Resign and announce elections," he added.
Khan, a former star cricket player, claims the May 2013 elections that Sharif won were rigged and has called for a fresh round of elections.
A second antigovernment rally also heading to Islamabad was led by populist cleric Tahir ul-Qadri, who demanded Sharif's arrest over what he alleged was the murder of his supporters.
Qadri issued a 48-hour ultimatum to the government to accept his demand, and threatened that he would not be responsible for any repercussions afterward.
The unrest has raised questions about Pakistan's stability at a time when the army is waging an offensive against Pakistani Taliban militants in the country's lawless tribal areas and when the influence of sectarian militant groups is growing.
Clashes erupted in the eastern city of Gujranwala on August 15 as thousands of antigovernment protesters led by Khan headed toward Islamabad.
Officials from Khan's Tehrik-e Insaf party said shots were fired at their convoy, a claim police have denied.
In Islamabad, authorities have blocked roads with shipping containers and barbed wire in an effort to control the marches, and riot police have been deployed across the city.
Members of Sharif's party have suggested the protests are secretly backed by elements in the military, which has had a troubled relationship with Sharif.
The military has been frustrated with the government, especially over the prosecution of former army chief and President Pervez Musharraf for treason.
There have also been differences between the government and the army on how to handle the Pakistani Taliban. The government has insisted on peace talks but eventually the army launched an offensive.