Sri Lankan opposition leader Mahinda Rajapaksa was appointed prime minister on Friday after President Maithripala Sirisena dismissed the incumbent in a surprise move that threatens political turmoil in the Indian
Rajapaksa, a pro-China former president, ushered in billions of dollars of investment from Beijing to help rebuild the country following the end of a 26-year civil war against Tamil separatists in 2009.
But that investment has since put the tiny island in debt and forced it to hand over control of a strategic southern port to China, seen as part of Beijing's Belt and Road Initiative, drawing criticism from India and the United States.
Sirisena administered the oath of office to Rajapaksa after sacking Premier Ranil Wickremesinghe, who was away touring the south of the country, following months of infighting.
But Wickremesinghe later told reporters he remained the prime minister. "I have the majority and I remain as the prime minister and I will function as the prime minister," he said.
Rajapaksa later said "the people" requested his party take over the government and called on Wickremesinghe's supporters to respect democracy and the rule of law.
Under Sri Lanka's constitution, modeled on the French system of government, the president has executive powers while the prime minister heads the parliament.
There was no immediate reaction from India, which has long seen Sri Lanka, located just off its southern tip, as part of its area of influence and had been concerned about Rajapaksa's wooing of China. Both Rajapaksa and Wickremesinghe were in India and met Prime Minister Narendra Modi in recent weeks.
Underlining the risk of chaos in the islands, where the government had been under pressure over a misfiring economy, Media and Finance Minister Mangala Samaraweera said on Twitter that the appointment of Rajapaksa as prime minister was a violation of the constitution, which was amended in 2015 to curtail the powers of the president.
"This is an anti-democratic coup," Samaraweera tweeted.
State-run Rupavahini briefly went off-air when three ministers, including Samaraweera and Cabinet spokesman Rajitha Senaratne, tried to address the nation during a live program.
Earlier Sirisensa's United People's Freedom Alliance (UPFA) had said it would quit the ruling coalition, capping months of rising tensions between the president's bloc and Wickremesinghe's center-right United National Party (UNP).
UPFA lawmaker Susil Premajayantha told reporters that a new Cabinet would be sworn in soon.
Sri Lanka's $87 billion economy has been under pressure in recent years, with growth slowing to a 16-year low of 3.3 percent last year because of tight monetary and fiscal conditions, droughts and floods.
The ruling coalition had been further strained in recent days by strong criticism from Sirisena and his allies that ministers from Wickremesinghe's party did not act properly in investigating an alleged assassination plot to kill the president and former Defense Secretary Gotabaya Rajapaksa, the new prime minister's younger brother.