Police have launched an operation to clear Islamist protesters from an intersection linking the Pakistani capital with the garrison city of Rawalpindi, sparking other demonstrations across the country.
Hundreds of police in riot gear moved against the supporters of the Tehreek-i-Labaik Ya Rasool Allah party early today after a deadline expired at midnight.
The police action and reaction from protesters, who have camped out at the Islamabad site for the last 20 days, sent scores of injured police and protesters to hospital with injuries caused by stoning and respiratory problems from tear gas.
Hospital officials said more than 150 people were injured, most of them police.
News of the police intervention spread quickly, prompting sympathisers in cities around the country to take to the streets in a show of solidarity with the Islamabad protesters.
The situation prompted the country's regulatory body for electronic media to take TV broadcasts off the air.
Military chief General Qamar Javed Bajwa telephoned prime minister Shahid Khaqan Abbasi to suggest a peaceful handling of the protest, according to a tweet by spokesman Major General Asif Ghafoor.
Senior police spokesman Ismatullah Junejo said officers were swiftly clearing the venue as 300 protesters ignored the final warning to disperse.
He said none of the police carried firearms to avoid loss of life, instead using only tear gas and water cannons to disperse the protesters, but witnesses said at one point, when a police van came under attack and was set on fire, two officers aimed assault rifles at protesters.
Police lobbed tear gas canisters and used the water cannons while surrounding and arresting dozens of protesters who resisted by throwing rocks. The riot police used batons against protesters who resisted.
The government had made several attempts to resolve the stalemate through negotiations with the protesters, who have demanded the resignation of a law minister over an omitted reference to the Prophet Mohammed in a parliamentary bill.
The minister, Zahid Hamid, apologised for the omission saying it was a clerical error that was later corrected, but protest leaders were adamant and refused to clear the intersection unless the law minister resigned.
Saturday's police operation came after a court ordered the protest to stop because it was disrupting daily life.