COLOMBO (REUTERS, AFP, BLOOMBERG) - Sri Lanka’s Prime Minister Ranil Wickremesinghe was sworn in as the country’s acting president on Friday (July 15), a government official said.

Mr Wickremesinghe had already taken on the role after Mr Rajapaksa fled the country on Wednesday following months of anti-government protests.

The speaker of parliament in crisis-hit Sri Lanka had accepted a resignation letter from President Gotabaya Rajapaksa, having verified its authenticity after it was flown from Singapore late on Thursday (July 14), he told reporters.

“Gotabaya has legally resigned” with effect from Thursday, Mr Mahinda Yapa Abeywardana said on Friday, after Mr Rajapaksa notified the speaker from Singapore he was stepping down.

“I have accepted the resignation," Mr Abeywardana said. "From this point, we will move to constitutionally appoint a new president. It will happen quickly and successfully.”

He added: “With the proud distinction of being South Asia’s oldest democracy, we will conduct this in the most democratic and transparent way.”

The legislature will be summoned on Saturday, Mr Abeywardana told reporters at his residence. The agenda for the weekend meeting will be decided on Friday, and voting for the next president in parliament was scheduled for July 20.

“I hope to complete the process of electing a new president within seven days,” he said. “I seek the cooperation of all concerned to complete the constitutional requirements.”

Under Sri Lanka’s constitution, Prime Minister Ranil Wickremesinghe – whose departure is also being demanded by protesters –  will remain acting president until parliament can elect an MP to succeed Mr Rajapaksa for the rest of his term.

Mr Wickremesinghe is also the first choice of the ruling party to take over full time, though no decision has been taken.

The opposition’s nominee is Mr Sajith Premadasa, while the potential dark horse is senior lawmaker Dullas Alahapperuma.

Sri Lanka’s opposition parties are now trying to cobble together an all-party government and pick candidates who can take over from Mr Rajapaksa and Mr Wickremesinghe

Mr Rajapaksa submitted his resignation late Thursday after arriving in Singapore from the Maldives, where he initially escaped after demonstrators overran his palace at the weekend.

His departure came after months of protests over what critics said was his mismanagement of the island nation's economy, leading to severe hardships for its 22 million people.

Mr Rajapaksa would be the first president to resign since Sri Lanka adopted a presidential system of government in 1978.

The news of Mr Rajapaksa’s resignation, first sent by an e-mail to the speaker before a hard copy was delivered to the speaker, triggered jubilation in Sri Lanka’s main city Colombo, where protesters massed outside the presidential secretariat.

“We are so happy today that he resigned and we feel that when we, the people, come together, we can do everything,” said Mr Arunanandan, 34, a school teacher who had been camping at the main protest site opposite the presidential secretariat for the past three months. “We are the real power in this country.”

Crowds set off firecrackers, shouted slogans and danced ecstatically at the Gota Go Gama protest site, named mockingly after Mr Rajapaksa’s first name.

A curfew imposed in the area on Thursday was lifted early on Friday, police spokesman Nalin Thalduwa said.

Street protests against Sri Lanka’s economic crisis have simmered for months and came to a head last weekend when hundreds of thousands of people took over government buildings in Colombo, blaming the Rajapaksa family and allies for runaway inflation, shortages of basic goods, and corruption.

Sri Lanka had begun preliminary discussions with the International Monetary Fund (IMF) about a potential bailout loan, but these have been interrupted by the latest government chaos.

IMF spokesman Gerry Rice told reporters on Thursday that the organisation's staff were still in contact with technical-level government officials but hoped to resume high-level dialogue “as soon as possible".

Mr Rajapaksa, his wife Ioma and their two bodyguards arrived in Singapore from the Maldives on board a Saudia airline flight.

The former Maldivian president Mohamed Nasheed was believed to have played a behind-the-scenes role in getting him out of the country, and said Mr Rajapaksa feared he would be killed if he remained.

"I believe the president would not have resigned if he were still in Sri Lanka, and fearful of losing his life," Mr Nasheed posted on Twitter.

Singapore's foreign ministry confirmed on Thursday night that Mr Rajapaksa was allowed to enter the Republic for a "private visit", adding: "He has not asked for asylum and neither has he been granted any asylum."

Mr Rajapaksa is expected to look to stay in Singapore for some time, according to Sri Lankan security sources, before potentially moving to the United Arab Emirates.

The spiralling economic crisis led to Sri Lanka defaulting on its US$51 billion (S$71.6 billion) foreign debt in April, and it is in talks with the IMF for a possible bailout.

The island has nearly exhausted its already scarce supplies of petrol, with the government ordering the closure of non-essential offices and schools to reduce commuting and save fuel.

In Colombo, demonstrators earlier left several of the emblematic state buildings they had taken over in recent days after Mr Wickremesinghe instructed security forces to restore order and declared a state of emergency.

"We are peacefully withdrawing from the Presidential Palace, the Presidential Secretariat and the Prime Minister's Office with immediate effect, but will continue our struggle," said a spokeswoman for the protesters.

Witnesses saw dozens of activists leave Mr Wickremesinghe's office as armed police and security forces moved in.

Hundreds of thousands of people had visited the prime minister's compound since it was opened to the public after he fled and his security guards backed down.

By Thursday afternoon, the gates were closed, with armed guards posted both inside and outside.

Police said a soldier and a constable were injured in clashes with protesters outside the national parliament as security forces beat back an attempt to storm the legislature.

Protesters also left the studios of the main state television station after breaking in on Wednesday.

The main hospital in Colombo said about 85 people were admitted with injuries on Wednesday, with one man suffocating to death after being tear-gassed at the premier's office.

The military and the police were issued fresh orders Thursday to firmly put down any violence, and warned troublemakers they were "legitimately empowered to exercise their force".

But student Chirath Chathuranga Jayalath, 26, said: "You cannot stop this protest by killing people. They'll shoot our heads but we do this from our hearts."