Veteran politician Ranil Wickremesinghe was sworn in as Sri Lanka's new president on Thursday, a day after winning a vote in parliament and urging the island nation to come together to find a way out of its worst economic crisis in decades.

The six-time prime minister succeeded Gotabaya Rajapaksa who fled Sri Lanka and resigned from his post last week after mass protests over his handling of the economy. The swearing-in ceremony was conducted in parliament, and presided over by the country's chief justice.

The country of 22 million people has been crippled by a severe financial crisis, with a lack of foreign currency leading to shortages of essentials including fuel, food and medicines.

Sri Lanka received fresh diesel supplies over the weekend, and the main state-run distributor, Ceylon Petroleum Corporation, will restart sales under a new rationing system from Thursday onwards, the power and energy ministry said.

The protest movement that pushed out Rajapaksa — the first sitting Sri Lankan president to quit office — remained largely muted, despite Wickremesinghe's unpopularity among some sections of the population.

Only a handful of people were present outside the presidential secretariat on Thursday, a colonial-era building that was stormed by a sea of protesters earlier this month along with the president and prime minister's official residences.

But some have vowed to fight on against Wickremesinghe.

“We won't give up because what the country needs is a total system change,” said Pratibha Fernando, a protester at the secretariat. “We want to get rid of these corrupted politicians, so that's what we are doing.”

Hours after winning the parliamentary vote on Wednesday, Wickremesinghe appeared to distance himself from the powerful Rajapaksa family that has dominated politics in Sri Lanka for decades.

“I am not a friend of the Rajapaksas. I am a friend of the people,” he told reporters after praying at a Buddhist temple in the commercial capital Colombo.

Wickremesinghe, who earlier served as prime minister and finance minister under Rajapaksa, has been involved in negotiations with the International Monetary Fund (IMF) for a bail out package worth up to $3 billion.

Sri Lanka is also looking for assistance from neighbouring India, China and other international partners.