The Supreme Court of the Maldives is to decide Sunday on President Abdulla Yameen's petition to overturn his defeat in last month's election, a move that could bring international sanctions.
The tiny Indian Ocean archipelago, which straddles the main east-west international shipping lanes, has seen political tensions escalate as Yameen jailed or exiled all his main opponents during his five-year rule.
After initially conceding defeat in the September 23 presidential election, Yameen mounted a challenge on Thursday asking the Supreme Court to annul the results and call a fresh vote.
Despite opposition fears of rigging in favour of Yameen who has ruled with an iron fist since 2013, the election was endorsed by the international community as free and fair.
Yameen was due to hand over power to the opposition candidate, Ibrahim Mohamed Solih, on November 17, but the latest court action risks pushing the country back into unrest, the opposition has said.
However, the strongest warning came from the United States which said it will take "appropriate measures" if Yameen fails to ensure a smooth transition of power.
"The US is concerned by troubling actions" by Yameen "that threaten to undermine the will of the Maldivian people, and will consider appropriate measures against anyone who undermines a peaceful transfer of power in #Maldives," a State department spokesman, Robert Palladino, said on Twitter.
The United States had previously warned of targeted sanctions if Yameen's administration attempted to rig the September vote won by Solih, who secured 58.4 percent against Yameen's 41.6 percent.
The Supreme Court hearing is due to start at 1:00 pm (0800 GMT) in the upmarket tourist destination which is also at the centre of a tussle for influence between India and China.
Yameen has courted China's backing while the opposition has said it wants to renegotiate huge loans Yameen had taken from Beijing.
Threat to stability
Hamid Abdul Ghafoor, Colombo-based spokesman for the opposition Maldivian Democratic Party (MDP), said the legal challenge was an attempt by Yameen to create unrest.
The country's Joint Opposition, which includes the MDP, has asked Yameen to withdraw the "blatantly unsubstantiated case, and to step aside and to facilitate a peaceful, and smooth transition."
The opposition has also urged state institutions, including the courts and the security forces, to uphold the will of the people.
"Maldivians used the ballot to defeat the dictatorial regime. Yameen must not be allowed to perverse the hard-won opportunity for all Maldivians to attain meaningful democracy and stability," the Joint Opposition said in a statement at the weekend.
Apart from his political foes, Yameen has jailed the chief justice and another supreme court judge after accusing them of trying to topple him in February.
Yameen had initially suspended the court, parliament and the constitution when he declared a state of emergency when parliament was about to impeach him in February.
Three of the remaining supreme court justices have been restored, but the opposition has said they had no faith in the judiciary to deliver justice while Yameen remained in power.
However, several high profile political prisoners, including Yameen's estranged half-brother Maumoon Abdul Gayoom have been released on bail since the election results were officially announced a week after the vote.