COLOMBO - Opposition leaders in the Maldives including two former heads of state have asked the Supreme Court to remove the president and investigate corruption allegations against him.

The opposition Maldivian Democratic Party (MDP) said Monday that the leaders had signed the petition asking the top court to suspend President Abdulla Yameen. It was filed on Sunday after attempts to topple Yameen through a vote in parliament failed when the president deployed the military, before unleashing a fresh crackdown against dissidents.

Almost all key opposition leaders and a number of ruling party dissidents have either been jailed or gone into exile in the Maldives. The signatories include the country's first democratically elected leader Mohamed Nasheed, who lives in exile since he was jailed on terrorism charges in a case widely seen as politically motivated.

Yameen's half brother and former president Maumoon Abdul Gayoom, who has joined key opposition figures ahead of general elections due later this year, also signed.

They accuse Yameen of "unprecedented corruption, including unjust enrichment from appropriation of state properties and funds for personal benefit, for the benefit of his family and political associates," according to the MPD statement.

It was not immediately clear whether the highest court would take up the petition.

Yameen took office in 2013 after winning a controversial run-off election against Nasheed.

The former president was jailed for 13 years in 2015, but granted prison leave in 2016 for medical treatment in London, where he secured political asylum.

A UN panel has ruled that his imprisonment was illegal and ordered the regime to pay him compensation.

The United States has said democracy is under threat in the strategically located archipelago, which sits on key international shipping lanes.