Pakistani opposition leader Imran Khan ordered his supporters yesterday to take to the streets and stand up against security forces after at least three people were killed in clashes between protesters and police in the capital overnight.
Pakistan's army commanders, meanwhile, expressed "serious concern" over the violent turn of events in Islamabad.
After a lengthy four hour meeting at the General Headquarters with army chief Gen Raheel Sharif in the chair yesterday, Pakistan Army corps commanders came out with a statement "reaffirming support to democracy".
In a statement, the army "reiterated that the situation should be resolved politically without wasting any time and without recourse to violent means."
"Further use of force will only aggravate the problem," it added.
The violence in Islamabad began Saturday night after thousands of supporters of Khan and firebrand cleric Tahir ul Qadri tried to storm Prime Minister Nawaz Sharif's house using cranes to remove barricades.
By yesterday afternoon, clashes were continuing between police in riot gear and a few hundred protesters. Many protesters had come armed with batons and slingshots.
Shipping containers were set ablaze, several vehicles stood torched, and hundreds of teargas canisters lay strewn on the ground on Islamabad's normally pristine Constitution Avenue following more than 15 hours of battle.
The opposition groups marched to the capital of the coup-prone country on August 15 demanding the resignation of Sharif, triggering a crisis that has raised the spectre of military intervention.
Khan, an outspoken cricketer-turned-politician, told his supporters in central Islamabad he would not back down from his demand for Sharif to resign and called on more protesters to join him.
"I am prepared to die here. I have learnt that government plans a major crackdown against us tonight," he said. "I am here till my last breath."
Raising the possibility of another night of clashes, Khan told the cheering crowd to directly challenge security forces protecting the parliament and the prime minister's house.
"The way you stood up last night, you have to stand up today also," he said. "We will face them and make them run away this time."
Tahir ul-Qadri also said protests would not subside unless Sharif resigned.
"State atrocities have reached their peak," he told his supporters from atop a shipping container. "Imran khan and Dr Qadri are fighting this war together."
At least 481 injured, including at least 118 women and 10 children, were rushed to the city's two major hospitals, according to officials. At least 92 police were among the wounded.
Sharif, who swept to office in the country's first democratic transition of power last year, has firmly resisted opposition calls for him to resign while agreeing to meet their other demands such as an investigation into alleged fraud during last year's election.
His office reiterated yesterday evening that his resignation was out of the question.
Earlier, information minister Pervaiz Rashid had said the government remained open to restarting negotiations.
"They wanted their demands to be met at gunpoint but still, our doors are open for talks."
Himself ousted in a coup in 1999 during an earlier stint in office, Sharif still has a difficult relationship with the army. Even if he survives this crisis, he will remain significantly weakened and sidelined on key issues such as foreign policy and security.
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. We are hopeful. Insh'allah (God willing) the army will save us, they will do something for us," said a female protester in her twenties called Ammara.