Sri Lanka deployed thousands of troops and police on Tuesday to enforce a curfew after five people were killed in the worst violence in weeks of protests over an unprecedented economic crisis.

Nearly 200 were also wounded Monday as prime minister Mahinda Rajapaksa resigned, but that did little to calm public anger.

He had to be rescued in a pre-dawn operation by the military Tuesday after thousands of anti-government protesters stormed his official residence in Colombo overnight, with police firing tear gas and warning shots to keep back the crowd.

"After a pre-dawn operation, the former PM and his family were evacuated to safety by the army," a top security official said. "At least 10 petrol bombs were thrown into the compound."

The Rajapaksa clan's hold on power has been shaken by months of blackouts and shortages in Sri Lanka, the worst economic crisis since it became independent in 1948.

President Gotabaya Rajapaksa remains in office, however, with widespread powers and command over the security forces.

After weeks of overwhelmingly peaceful anti-government demonstrations, violence broke out Monday when Mahinda Rajapaksa's supporters -- bussed into the capital from the countryside -- attacked protestors with sticks and clubs.

"We were hit, the media were hit, women and children were hit," one witness said, asking not to be named.

Police fired tear gas and water cannons to disperse crowds and declared an immediate curfew in Colombo, a measure later widened to include the entire South Asian nation of 22 million people.

Authorities said the curfew will be lifted Wednesday morning, with government and private offices, as well as shops and schools, ordered to remain shut on Tuesday.

Despite the curfew, anti-government protesters defied police to retaliate against government supporters for the attacks late into Monday night.

Outside Colombo, ruling party lawmaker Amarakeerthi Athukorala shot two people -- killing a 27-year-old man -- after being surrounded by a mob of anti-government protesters, police said.

"He then took his own life with his revolver," a police official said.

Athukorala's bodyguard was also found dead at the scene, police said.

Another ruling party politician who was not named opened fire on protesters, killing two and wounding five in the deep south of the island, police added.

Angry crowds set alight the homes of more than a dozen pro-Rajapaksa politicians, along with some vehicles, while buses and trucks used by the government loyalists in and around Colombo were also targeted.

Several Rajapaksa homes were torched in different parts of the country, while a family museum in their ancestral village was trashed.

Doctors at the main Colombo National Hospital intervened to rescue wounded government supporters, with soldiers breaking open locked gates to ferry in the wounded.

"They may be murderers, but for us they are patients who must be treated first," a doctor shouted at a mob blocking the entrance to the emergency unit.

Mahinda Rajapaksa, 76, said he was resigning to pave the way for a unity government.

But it was unclear if the opposition would join any unity administration, having before refused to govern with any members of the Rajapaksa family.

Under Sri Lanka's political system, even with a new unity government, the president will have the power to appoint and fire ministers as well as judges, and enjoy immunity from prosecution. (AFP)