Former Sri Lankan President Mahinda Rajapaksa was sworn in as Prime Minister on Friday after President Maithripala Sirisena sacked incumbent Ranil Wickremesinghe in a surprise move that threatens political turmoil in the Indian Ocean nation.

The appointment was confirmed in a statement from the President’s office, but Wickremesinghe later told local TV he remained the Prime Minister. “I retain the confidence of the House. I am the Prime Minister and I have the majority,” Wickremesinghe said. “According to the Constitution, I’m the Prime Minister.”

Local TV pictures had shown Rajapaksa, who last month led Opposition protests against the government, being sworn in before Sirisena, surrounded by a number of Opposition legislators.

The Sri Lanka government had been under pressure over a misfiring economy.

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 Centre-Right United National Party (UNP).

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 defence secretary Gotabaya Rajapaksa, the new Prime Minister’s younger brother.

The alleged plot briefly threatened to cause tension between Sri Lanka and India.

Wickremesinghe was in India just a week ago for a scheduled bilateral meeting with Prime Minister Narendra Modi days after Lankan President Sirisena is said to have told his cabinet about the alleged RAW plot to assassinate him.

An Indian national arrested for possible links to the alleged assassination plot has been sent to a mental hospital, PTI quoted police as saying in Colombo on Friday. Marceli Thomas has been put under the care of doctors at a hospital of mental care near Colombo, police spokesman Ruwan Gunasekera said.

Thomas was arrested late last month following a complaint by Namal Kumara, who claimed to be representing an “anti-corruption force”, and who had alleged there was an assassination plot.

Sirisena himself had led the effort at damage control by calling up Modi to “categorically” reject the reports in a section of the media about “him alluding to the involvement of India in any manner whatsoever in an alleged plot to assassinate the President and a former defence secretary of Sri Lanka”.

The reports on the alleged assassination plot did state that while Sirisena said “Indian intelligence agency RAW was engaged in activities to assassinate him”, Modi himself may not be aware of the plan.

Besides Sirisena’s telephone conversation with Modi to clear the air on the eve of Wickremesinghe’s India visit, he also met the Indian high commissioner in Colombo.

Separately, three media releases were issued by various wings of the Sri Lankan government to deny the report, and this was officially taken note of by India too.

Asked about the reports of the assassination plot, Indian foreign ministry spokesman Raveesh Kumar had said on October 18: “The media reports have been outrightly dismissed and not through one but three different press releases issued by different wings of the Sri Lankan government….”

Kumar underlined that all shades of political opinion in Sri Lanka are in favour of a close relationship with India, seeking to quell speculation over Colombo’s growing proximity to Beijing in recent years.