Thousands of protesters marched around Prime Minister Sharif's house to put pressure on him to resign Saturday. (Reuters)

Pakistani police fired tear gas at thousands of protesters marching toward the prime minister’s home in the capital Saturday, blanketing the route with clouds of white smoke and scattering demonstrators.

Police also fired rubber bullets to disperse the crowd, injuring some protesters. At least a dozen were taken to a nearby hospital, police said.

March leaders Imran Khan and anti-government cleric Tahirul Qadri called for the demonstration to move to the residence from separate massive rallies in front of the Parliament, where they have been staging a sit-in for days. Some 20,000 police officers in riot gear are charged with blocking the procession.

In speeches, Khan, a cricket legend turned politician, and Qadri said they will remain peaceful and urged security forces to abstain from using force against the protesters.

The two allege that Prime Minister Nawaz Sharif won the 2013 national election with massive voter fraud. They demand that he step down.

Both Khan and Qadri, a dual Pakistani-Canadian citizen with a wide following, also are demanding reforms in Pakistan’s electoral system to prevent future voter fraud.

Sharif, who is backed by Parliament and many political parties, has said he will not step down. Government negotiators are trying to persuade Qadri and Khan to end their protest and abandon the demand for Sharif’s resignation.

The demonstration began with a march from the eastern city of Lahore on the country’s independence day, Aug. 14. Khan and Qadri had called for millions of protesters to join in, but the numbers have not exceeded tens of thousands. The protesters’ presence and heightened security measures have disrupted normal life and badly harmed business in the capital. The rallies have remained festive, with families picnicking and men and women dancing to drums and national songs.

Riot police initially showed restraint during Saturday’s march, but when the crowd started removing shipping containers used as barricades, they fired salvos of tear gas canisters, forcing the protesters back. TV footage showed protesters, including women and children, scattering in retreat. Some fell to the ground, and dozens were being treated in a hospital. Many, including two children, were shown being treated for effects of tear gas.

Police refused to give any estimates about the size of the crowd that had been headed toward the prime minister’s residence.

Police official Farman Ali said the injured were moved to a government hospital.

“They fired tear gas shells at us,” said Ahsanullah Fakhri, 28, who was bleeding from one leg, as he exited an ambulance with about seven other protesters who had multiple minor wounds.

“I think they are also firing some bullets, I think rubber bullets,” he added.

Khan described the police action against the crowd as illegal.

“Now we will show this government,” he said. “We will call for countrywide agitation, and we will jam the whole of Pakistan.”

Interior Minister Chaudhry Nisar Ali Khan quickly visited the scene to boost police morale.

“A group wanted to capture the prime minister’s house and other buildings,” he said. “We are under oath, and the police as well, to protect the state assets.”

— Associated Press