Sri Lankan Prime Minister Mahinda Rajapaksa resigned on Monday, hours after his supporters attacked anti-government protesters outside embattled President Gotabaya Rajapaksa's office, leaving at least 78 people injured and prompting authorities to impose a nationwide curfew and deploy army troops in the capital.

A legislator, Amarakeerthi Athukorala, from Sri Lanka's ruling party was found dead on Monday after a clash with anti-government protesters outside the capital Colombo, reports ndtv.com

At least two Cabinet ministers have also announced their resignations.

Prime Minister Mahinda, 76, sent his resignation letter to the President Gotabaya Rajapaksa after violent scenes were witnessed in Colombo.

The violence occurred as pressure mounted on the embattled government led by his younger brother and President Gotabaya to form an interim administration to overcome the worst economic crisis facing the country.

Curfew was imposed islandwide with immediate effect until further notice, a police spokesperson was quoted as saying by the local media. A military contingent was deployed to the protest site to assist law enforcement.

At least 78 people were injured as supporters of Prime Minister Mahinda Rajapaksa on Monday attacked anti-government demonstrators gathered at a protest site near his official residence to demand for the premier's resignation.

Sri Lanka is currently in the throes of unprecedented economic turmoil since its independence from Britain in 1948. The crisis is caused in part by a lack of foreign currency, which has meant that the country cannot afford to pay for imports of staple foods and fuel, leading to acute shortages and very high prices.

Thousands of demonstrators have hit the streets across Sri Lanka since April 9 seeking resignation of President Gotabaya and Prime Minister Mahinda, as the government ran out of money for vital imports; prices of essential commodities have skyrocketed and there are acute shortages in fuel, medicines and electricity supply.

'Nothing would deter me'

Earlier, Rajapaksa told his thousands of supporters gathered outside his house that nothing would deter him. "I am so used to seeing protests and agitations, nothing would deter me. I am experienced enough to face any situation," Rajapaksa said.

A tense situation prevailed as a group of supporters of Prime Minister Mahinda Rajapaksa attacked the protesters outside the 'MainaGoGama', a protest site near Temple Trees, the official residence of the Prime Minister, Daily Mirror, an online news platform, reported.

The tents opposite Temple Trees were dismantled by a mob, Lanka First, a leading news network, reported.

Police use water cannons

On Monday, police used water cannons to disperse the unruly SLPP protestors who are at the Galle Face green protest site, Hiru News website reported.

The police formed a human chain to prevent the protesters from entering GotaGoGama.

However, the mob pushed their way past the police human chain and attacked GotaGoGama.

A military contingent was deployed to the protest site to assist law enforcement.

Opposition leader visits site

Opposition leader of the Samagi Jana Balavegaya Sajith Premadasa visited the GotaGoGama protest site to assess the situation.

The Opposition sources said a group had also attacked Premadasa and his colleagues as he arrived at the presidential secretariat protest site.

It accused Mahinda Rajapaksa of instigating his supporters. Later, the government deployed Army troops to bring the situation under control.

The Rajapaksa brothers - President Gotabaya Rajapaksa and Prime Minister Mahinda Rajapaksa - have so far defied calls for their resignation.

State of emergency

In a special Cabinet meeting on Friday, President Gotabaya Rajapaksa declared a state of emergency with effect from Friday midnight. This is the second time that an emergency was declared in Sri Lanka in just over a month as the island nation was in the grip of the worst economic crisis.

Sri Lanka is currently in the throes of unprecedented economic turmoil since its independence from Britain in 1948.

The crisis is caused in part by a lack of foreign currency, which has meant that the country cannot afford to pay for imports of staple foods and fuel, leading to acute shortages and very high prices.

Thousands of demonstrators have hit the streets across Sri Lanka since April 9, as the government ran out of money for vital imports; prices of essential commodities have skyrocketed and there are acute shortages in fuel, medicines and electricity supply.