The opposition lost the last elections in 2013 in controversial circumstances
The Maldivian opposition said Monday that government warnings of a murky plot to destabilise the honeymoon islands were a "cowardly" attempt by the ruling party to delay next month's presidential elections.
Defence Minister Adam Shareef Umar, a loyalist to President Abdulla Yameen, said police and defence forces had been placed on alert following an unspecified threat to national security.
No further details have been provided of the alleged plot.
But the Maldives opposition seized on the remarks, suggesting the strongman president who has ruled with an iron fist since 2013 was generating fear to justify delaying September's poll.
"President Yameen is running scared from an election he knows he can't win," Hamid Abdul Ghafoor, a spokesman for the Maldivian Democratic Party, said from the opposition base in Colombo.
"This is why he's inventing cowardly excuses to cancel or delay the election."
The archipelago nation has been on edge since Yameen - who has jailed or exiled almost all his opponents - imposed a 45-day state of emergency in February and arrested top judges accusing them of fomenting a coup against him.
The president has also not officially registered his intention to run again for office, raising further suspicions. He has until August 10 to file his nomination papers.
The opposition lost the last elections in 2013 in controversial circumstances.
The Supreme Court annulled the results of the first round of voting when opposition candidate, and former president, Mohamed Nasheed was in the lead.
The subsequent vote was then twice delayed, allowing Yameen time to forge alliances that helped him narrowly win the contested run-off.
Nasheed, who was jailed in 2015 in what the UN described as a politically motivated trial, was disqualified from running in the election on September 23. He lives in exile.
The opposition has fielded MDP's parliamentary leader Ibrahim Mohamed Solih as the candidate to challenge Yameen.
Many other opposition figures are imprisoned or banished abroad but Solih and the MDP have vowed to clear the way for all political dissidents to return and participate in government if victorious in the election.
The Supreme Court in February ordered that MPs sacked by the president be restored to power and dissidents freed from jail, sparking a crackdown by Yameen that plunged the islands into turmoil.
The Maldives' chief justice and Supreme Court judges were arrested, along with Yameen's half-brother Maumoon Abdul Gayoom, a former dictator who ruled for 30 years until 2008.
The US and European Union have expressed deep concern over Yameen's actions, and rights activists have called for sanctions on the president and his aides.