Pakistan's powerful Army said on Sunday any further use of force to resolve an escalating political crisis would only worsen the situation, after weeks of protests demanding Prime Minister Nawaz Sharif's resignation turned violent.

Night-long clashes between security forces and anti-government protesters left four persons dead and nearly 500 others injured in the federal capital.

The top brass of the Army headed by General Raheel Sharif held an urgent meeting in the garrison city of Rawalpindi to discuss the crisis, prompting speculation that the military could take decisive action to end the crisis in a nation where power has usually changed hands via coups rather than elections.

The police battled throngs of protesters led by Pakistan Tehreek-i-Insaf (PTI) chairman Imran Khan and Pakistan Awami Tehreek (PAT) Chief Dr Tahir ul-Qadri.

The clashes broke out late last night when the demonstrators who have laid a siege to the heart of the Pakistani establishment, housing the Presidency, the National Assembly, the Supreme Court, the Prime Minister's Office, sought to storm PM Nawaz Sharif's residence nearby after breaking through the police barricade.

The demonstrators —demanding Sharif's resignation over alleged rigging during last year's elections — were held back with tear gas, batons and rubber bullets outside the PM's house.

After a night of clashes, protesters regrouped on Sunday and repeatedly clashed with the heavy deployment of security forces. In a brief statement, the Army reaffirmed its commitment to democracy and said the crisis had to be solved politically.

"Further use of force will only aggravate the problem. It was once again reiterated that the situation should be resolved politically without wasting any time and without recourse to violent means," it said.

A security official said the meeting called by General Sharif was initially planned for tomorrow but it was rescheduled due to "deteriorating internal security situation". Amid turmoil, PM Sharif also cut short his weekend stay in Lahore to return to the Capital and was immediately closeted in consultation with top aides. Amid fluid situation emerging from series of developments, media reports said the government has withdrawn the police from the 'red zone' of sensitive official buildings leaving their security to the Army troops deployed earlier on its request.

Cricketer-turned-politician Khan vowed to fight till the last breath and asked Pakistanis to rebel against the "illegal" regime while Qadri alleged seven of his supporters were killed by security forces which could not be confirmed.