Sri Lanka has plunged deeper into crisis after president Maithripala Sirisena called a snap election, leaving the country facing a further two months of damaging political paralysis with a pair of bitter rivals claiming to run his government.

In what opponents condemned as an illegal move, Sirisena dissolved the country’s parliament on Friday in a gamble that a new election will secure backing for his preferred candidate as prime minister, over an ousted premier who has refused to leave, reports theguardian.com.

Sirisena signed a decree dismissing the island’s 225-member assembly and scheduled parliamentary elections for 5 January, nearly two years ahead of schedule.

Hours earlier Sirisena’s party admitted it did not have enough votes to support former president Mahinda Rajapakse against rival claimant and ousted premier Ranil Wickremesinghe, who has refused to leave his post.

The two have been battling for the prime minister’s post for two weeks as international concern grows over the mounting turmoil.

There was no immediate comment from Wickremesinghe, but his United National Party, or UNP, said it will challenge Sirisena’s sacking of the legislature.

‘This dissolution by the President is illegal and goes against the constitution,’ the UNP said on Twitter. ‘We will be fighting this to ensure that democracy reigns supreme in the country.’

‘He has robbed the people of their rights and the democracy that we have enjoyed,’ the UNP said.

Sirisena had come under increased international pressure from the United States, the United Nations and the European Union to allow parliament to vote on which prime minister should form a government.

Washington swiftly criticised Sirisena’s latest move.

‘The US is deeply concerned by news the Sri Lanka parliament will be dissolved, further deepening the political crisis,’ the US State Department said in a statement on Twitter.

‘As a committed partner of Sri Lanka, we believe democratic institutions and processes need to be respected to ensure stability and prosperity,’ it said.

Sirisena’s United People’s Freedom Alliance admitted ahead of the president’s stunning announcement that they had failed to secure enough cross-over MPs to win a confidence vote.

By avoiding a test of his majority on the floor of the House, Rajapakse will remain caretaker prime minister until elections are concluded and a new parliament meets on 17 January.

Sirisena sparked the crisis on 26 October by sacking Wickremesinghe and replacing him as prime minister with Rajapakse, the country’s authoritarian president from 2005 until 2015.

Sirisena had claimed on Monday he had the support of 113 legislators when he sacked Wickremesinghe. But the admission of a lack of a majority had fuelled speculation that he might sack the legislature and go for a snap election.

The leftist People’s Liberation Front, which regards the sacking of Wickremesinghe as unconstitutional, accused Sirisena of trying to consolidate his power grab.

‘Dissolving parliament at this time is illegal and goes against the constitution,’ the party’s general secretary, Tilvin Silva, told reporters.

Sirisena suspended parliament to give himself more time to engineer defections, according to the opposition. Several legislators have said they were offered millions of dollars to switch allegiance and at least eight have already jumped to the president’s side.

Wickremesinghe, who has not left the Temple Trees residence since his sacking, maintains that the action against him was unconstitutional and illegal, and insists his group can muster a majority.

Under pressure from the UN, the US and the EU to allow a parliamentary vote, Sirisena agreed three times to lift the suspension but changed his mind each time.

The EU said on Friday, before the dissolution, that the crisis had scarred the Indian Ocean island’s international reputation.

In a joint statement with Norway and Switzerland, the EU called for parliament to reconvene and hold an immediate vote.

The power struggle on the island of 21 million people has paralysed much of the administration, according to legislators on both sides of the dispute.