Pakistan's government said it was trying to reopen talks with opposition groups after bloody overnight clashes between police and protesters outside the prime minister's residence left three dead and hundreds injured.
Sporadic clashes continued yesterday between police in riot gear and a few hundred protesters, as thousands more lay on the grass and slept. Many protesters had come armed with batons and slingshots.
Several vehicles stood torched and hundreds of tear gas canisters lay strewn on the ground on Islamabad's normally pristine Constitution Avenue following more than 12 hours of battle.
Thousands of followers of politician Imran Khan and firebrand cleric Tahir ul-Qadri have been camped outside parliament since August 15 demanding the resignation of Prime Minister Nawaz Sharif, triggering a crisis that has raised the spectre of military intervention.
Opposition groups - who claim last year's election which swept Sharif to power was rigged - tried to storm the prime minister's official residence on Saturday night, using cranes to remove barricades.
Information Minister Pervaiz Rashid said yesterday the government remained open to restarting negotiations to end the situation peacefully.
"The government did not initiate the clashes. They turned violent and tried to enter sensitive government buildings, which are the symbol of the state," he told the Geo News channel.
"They wanted their demands to be met at gunpoint but still, our doors are open for talks."
A Qadri follower who identified himself as Aziz complained: "This is democracy, this is democracy in Pakistan.
"It is more dangerous than military dictatorship; they don't allow people to make peaceful protests."
Addressing supporters earlier, former cricket hero Khan said: "I will not leave my people alone and keep fighting until we secure a real independence for Pakistan.
"The Sharif brothers have a lust for power. They are not sincere with the people or the country.
"We will get their resignations and put them in jail," Khan added, referring also to the prime minister's brother, Shehbaz Sharif, who is chief minister of Punjab state.
Neither Khan nor Qadri led their protests from the front, though Khan later tweeted a picture of himself standing on top of a shipping container which he said was being shelled by tear gas.
The Pakistan Institute of Medical Sciences reported two deaths - one man hit by a rubber bullet and another who died of a heart attack.
More than 400 injured, including dozens of women and a handful of children, were rushed to the city's two major hospitals. At least 79 police were among the wounded.
The crisis took on a new dimension on Thursday after it was announced the country's powerful army chief, General Raheel Sharif, would mediate.
Observers believe that if Sharif survives the crisis it will be at the cost of significant concessions to the army - including allowing ex-army chief Pervez Musharraf, currently on trial for treason, to leave the country.
But political analyst Mosharraf Zaidi said the protests had become difficult to contain and the opposition could be trying to get the military more directly involved.
"The single objective is to force Sharif to resign and possibly force the military to intervene," he said.
Zaidi also dismissed claims by the protest groups that they had not initiated the violence.
"You cannot build up emotions nationwide, but particularly [outside parliament], for 17 days - you cannot say, 'I want my tigers in the front and my women in the back' - you cannot be in attack formation and then claim you had no role in fomenting this violence," he said.
The protest leaders have drawn thousands to the streets of Islamabad, but their call has not mobilised mass support in a country of 180 million people.
But many of the protesters are now openly calling for the military - which has ruled Pakistan for half its existence - to return to power.
"Last night, the police used tear gas and rubber bullet against us. Now we are waiting for the help of the army," said a female protester called Ammara.