Malaysian opposition chief Anwar Ibrahim said Wednesday he had "formidable" support from MPs to form a new government, but the prime minister insisted he remained the country's legitimate leader.

The Southeast Asian nation has been in turmoil since an alliance that swept to power in 2018, which was headed by Mahathir Mohamad and included Anwar, collapsed in February amid bitter infighting. Muhyiddin Yassin became premier at the head of a coalition backed by a scandal-plagued party which had been ousted at the polls two years earlier, but with only a wafer-thin majority in parliament.

Speaking at a press conference in Kuala Lumpur, veteran politician Anwar -- who has long sought to become prime minister -- said he now had the backing of enough MPs to form the government and oust Muhyiddin. "Conclusively we have a strong, formidable majority," the 73-year-old said. "The government under the leadership of Muhyiddin Yassin has fallen."

However, there were immediately doubts over his claim as he did not reveal how many MPs were backing him or which parties they were from. A government must command the support of a majority of the 222 MPs in parliament. To form a new government Anwar must prove to the king, who formally appoints Malaysia's premiers, that he has enough support in parliament, and he has yet to meet the monarch.

He said an audience with the king originally planned for Tuesday had been postponed as the monarch was having medical treatment. The national palace confirmed a meeting had been scheduled.

'Political psychopath'

Muhyiddin appeared unshaken by the opposition leader's challenge, and challenged Anwar to go through the proper process to prove his claim to the premiership. "Until proven otherwise, the... government still stands firm and I am the legitimate prime minister," he said in a statement.

The parties backing Muhyiddin's coalition slammed Anwar's move as "cheap publicity". "His latest action highlights his greedy and power-crazy attitude which pays no heed to the country's political and economic stability, or the fate of the people who are badly affected by Covid-19," they said in a joint statement.

Other members of the government brushed off the move, with International Trade and Industry Minister Azmin Ali brandishing Anwar an "incorrigible liar and political psychopath". Anwar's move came ahead of weekend elections for the legislature in the eastern state of Sabah, which will be a major test of the current government's popularity.

Muhyiddin's administration has had the difficult task of leading Malaysia through the coronavirus pandemic, with the economy suffering its worst contraction in more than 20 years in the second quarter amid a strict lockdown. But restrictions have been eased and authorities have won praise for their handling of the outbreak, which has been relatively small -- Muhyiddin received a 69 percent approval rating in a survey earlier this month.

Long-time opposition leader Anwar was a key figure in the alliance that won a shock victory at landmark elections in 2018, toppling a scandal-plagued coalition that had ruled Malaysia uninterrupted for over six decades. Voters kicked out the old regime in large part due to anger at former premier Najib Razak's involvement in a massive financial scandal which saw billions looted from state coffers.

Mahathir, now 95, became prime minister for a second time and Anwar was released from jail, where he had been serving a sentence after being convicted of dubious sodomy charges. But the government collapsed amid tensions between rival factions over whether Mahathir would stick to a promise to hand power to one-time nemesis Anwar, and Muhyiddin seized power without an election.