Sri Lankan leftist president Anura Kumara Dissanayaka sworn in

Sri Lanka's first leftist president was sworn into office Monday vowing to restore public faith in politics after anger over the island nation's unprecedented economic crisis propelled him to a landslide poll win.

Self-avowed Marxist Anura Kumara Dissanayaka of the People's Liberation Front (JVP) took his oath at the colonial-era Presidential Secretariat in Colombo after trouncing his nearest rivals in Saturday's vote.

The previously fringe politician -- whose party led two failed uprisings that left tens of thousands dead -- saw a surge of support after the country's 2022 economic meltdown forced painful hardships on ordinary Sri Lankans.

Dissanayaka, 55, was sworn in by the chief justice in a ceremony attended by lawmakers, members of the Buddhist clergy and the military who sang the national anthem after the ceremony.

"I will do my best to fully restore the people's confidence in politicians," Dissanayaka said after taking the oath.

"I am not a conjurer, I am not a magician," he added. "There are things I know and things I don't know, but I will seek the best advice and do my best. For that, I need the support of everyone."

Dissanayaka succeeds outgoing president Ranil Wickremesinghe, who took office at the peak of the financial crisis following the government's first-ever foreign debt default and months of punishing food, fuel and medicine shortages.

Wickremesinghe, 75, imposed steep tax hikes and other austerity measures per the terms of an International Monetary Fund bailout.

His policies ended the shortages and returned the economy to growth but left millions struggling to make ends meet.

"I can confidently say that I did my best to stabilise the country during one of its darkest periods," he said in a statement after placing a distant third in Saturday's poll.

Shortly before the ceremony, Prime Minister Dinesh Gunawardena resigned, clearing the way for Dissanayaka to appoint his own cabinet.

Dissanayaka's party has said he wants to have his own cabinet until a fresh parliament is elected later this year. His JVP party has only three members in the 225-member parliament.

He has vowed to press ahead with the IMF rescue package negotiated by his predecessor last year but modify its terms in order to deliver tax cuts.

"It is a binding document, but there is a provision to renegotiate," Bimal Ratnayake, a senior member of Dissanayaka's party, told AFP.

Dissanayaka's party led two rebellions in the 1970s and 1980s that left more than 80,000 people dead before renouncing violence.

It had been a peripheral player in Sri Lankan politics in the decades since, winning less than four percent of the vote during the most recent parliamentary elections in 2020.

But Sri Lanka's crisis proved an opportunity for Dissanayaka, who saw his popularity rise after pledging to change the island's "corrupt" political culture.

The 55-year-old labourer's son was a JVP student leader during the second insurrection and has described how one of his teachers sheltered him to save him from government-backed death squads that killed party activists.

He counts famous Marxist revolutionary Che Guevara among his heroes.

Since his rise to popularity, he has softened some policies, saying he believes in an open economy and is not totally opposed to privatisation.