BANGKOK: Thailand's Prime Minister Prayuth Chan-ocha announced on Tuesday his retirement from politics, nine years after he took power in a military coup, and promised to stay in charge only temporarily.

His announcement was widely expected after his military-backed United Thai Nation party was thumped in a May 14 election, in which it won just 36 of the 500 house seats. He will remain caretaker premier until a new government is formed.

The former army chief, a staunch royalist, led a junta until an election in 2019 and was chosen by parliament to remain prime minister for four more years, an outcome his opponents insist was pre-determined.

Prayuth, 69, has denied that and on Tuesday said he had "achieved many successes".

"I as prime minister have worked hard to protect the nation, religion, monarchy for the benefit of the beloved people. The result is currently bearing fruit for the public," he said in a statement.

"I have tried to strengthen the country in all areas for stability and peace and overcame many obstacles domestically and internationally." I

In the nine years since his coup, Prayuth has survived multiple challenges via court cases, house confidence votes and street protests by opponents who saw him as an opportunist who lacked a public mandate.

His announcement comes as the new parliament prepares to convene on Thursday to hold a vote on who will be the next prime minister, an outcome far from certain.