Here's your 10-point cheatsheet to this big story:
The President's resignation comes on a day the protesters announced they would end their occupation of official buildings, including the presidential palace, presidential secretariat and the Prime Minister's office.
The Singapore government has said the former Sri Lankan President is on a "private visit" and has not applied for asylum.
Mr Rajapaksa while he was President enjoyed immunity from arrest, which he used to leave Sri Lanka. He stepped down only after he was outside the country to avoid the possibility of being detained.
Prime Minister Ranil Wickremesinghe has asked security forces to restore order and declared a state of emergency.
Witnesses saw dozens of activists leave Mr Wickremesinghe's office as armed police and security forces moved in, news agency AFP reported. "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," a spokeswoman for the protesters said.
Mr Rajapaksa is expected to stay in Singapore for some time, according to Sri Lankan security sources, before potentially moving to the United Arab Emirates, AFP reported.
Hundreds of thousands of people have visited Mr Rajapaksa'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 placed in and outside.
Mr Rajapaksa is accused of mismanaging the economy to a point where the country has run out of foreign exchange to finance even the most essential imports, leading to severe hardships for its 22 million people. Sri Lanka defaulted on its $51-billion foreign debt in April and is in talks with the International Monetary Fund 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.
Diplomatic sources said Mr Rajapaksa's attempts to secure a visa to the United States had been turned down because he had renounced his US citizenship in 2019 before running for President, AFP reported.
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