BANGKOK, Thailand — President Abdulla Yameen of the Maldives, who is under pressure to step down, faces allegations of corruption dating back more than a decade, including oversight of questionable oil sales to a Myanmar dictatorship under economic sanctions.
Mohamed Nasheed, who became the country’s first democratically elected president in 2008 but was forced to resign in 2012, contends that a state-owned company once led by Mr. Yameen sold nearly $300 million worth of oil to Myanmar’s military dictatorship in the early 2000s. Later, Mr. Nasheed said, nearly half the money disappeared.
At the time, the Myanmar regime faced strict sanctions from the United States and the European Union. Mr. Nasheed said the oil shipments had helped the regime circumvent the sanctions and hold on to power.
In his first public comments on the oil deal, Mr. Nasheed said he believed that his attempt as president to recover as much as $137 million of the missing money had been a significant factor in his ouster and subsequent imprisonment. He also contended that Mr. Yameen was now using the presidency to enrich himself, and that Mr. Yameen and his associates had received kickbacks from the sale of government-owned islands.
“President Yameen is very, very corrupt, and all the evidence is available,” Mr. Nasheed said in a recent telephone interview from London, where he lives in exile. “We are talking about hundreds of millions of dollars.”
Ibrahim Hussain Shihab, a spokesman for Mr. Yameen, said by email that the state’s trading organization had never sold oil to Myanmar during Mr. Yameen’s tenure. The spokesman also denied that Mr. Yameen had received illegal payments, whether from oil or land transactions or any other type of deals.
Addressing government land sales, Mr. Shihab said, “All such actions are to be carried out through transparent guidelines, and at no point will they personally benefit the president, his aides or any member of this administration financially.”
Mr. Yameen faces growing opposition because of the allegations about graft and his continuing purge of potential rivals. Some opponents have criticized a recent change in the law that will allow the government to sell islands without competitive bids.
The Maldives is Asia’s smallest country, with about 400,000 predominantly Muslim inhabitants. An archipelago in the Indian Ocean about 400 miles southwest of the tip of India, the Maldives consists of about 1,200 low-lying islands, making it among the world’s most vulnerable countries to rising ocean levels.
The country is dependent on foreign tourists, who sometimes pay thousands of dollars a night to stay in resorts built on spectacular atolls. Most Maldivians eke out a meager existence by fishing or working in the tourism industry.
Mr. Nasheed, a human rights and environmental activist, and Mr. Yameen, part of the Maldives’s longtime ruling family, have repeatedly clashed over the years.
Mr. Nasheed, 49, became something of a celebrity in the fight against climate change, and he was the subject of a 2011 documentary, “The Island President.” He once held a cabinet meeting underwater to call attention to the threat of global warming.
He was forced from office by Mr. Yameen’s allies and later spent nine months in prison on a terrorism conviction that was internationally condemned as a sham.
Mr. Yameen, 57, is the half brother of the longtime autocrat Maumoon Abdul Gayoom, who ruled the Maldives for 30 years. Their family and a handful of well-connected resort owners control most of the country’s wealth. Under Mr. Nasheed, the government sought to recover $400 million that it said Mr. Gayoom and his associates had looted.
Mr. Yameen served as a minister in his brother’s cabinet and held other top posts, including head of the State Trading Organization. He defeated Mr. Nasheed for the presidency in a 2013 election that Mr. Nasheed’s supporters contend was rigged.
Over the past year, Mr. Yameen’s government has been in a state of turmoil with frequent arrests, firings and resignations of top officials. Among them was former Vice President Ahmed Adeeb, who was convicted in June of plotting to kill President Yameen by planting a bomb on his yacht.
Mr. Nasheed said he had inadvertently discovered the Myanmar oil sales early in his presidency after ordering a carbon audit in a first step toward reducing emissions. Examiners were puzzled when they found records showing that the Maldives had become an oil exporter, he said. The Maldives does not produce any oil.
“We wanted to see how much oil we imported,” he said. “We found that the amount of oil exported from the Maldives far exceeded the amount we imported.”
The sellers used a double invoicing system to disguise the nature of the transactions, according to court affidavits and an audit report.
“They had bill of ladings issued so that it was apparently shipped to the Maldives, but on the high seas they would change this bill of lading and they would divert the oil to Burma,” Mr. Nasheed said, referring to Myanmar by its previous name.
Myanmar’s military dictatorship was under international sanctions for human rights violations, including keeping the opposition leader Daw Aung San Suu Kyi, a Nobel Peace Prize laureate, under house arrest. Myanmar generals were frequent visitors to the Maldives at the time, Mr. Nasheed said.
“Sanctions were biting really hard on them,” Mr. Nasheed said. “I think the regime survived all the way up to the recent election simply because now-President Yameen and the Maldives state oil company were supplying them with illegal oil.”
The United States and the European Union began easing some sanctions in recent years as Myanmar moved toward democracy. Ms. Aung San Suu Kyi’s party swept elections last year, and she now leads the country as its state councilor.
In 2011, Mr. Nasheed’s government began legal proceedings in Singapore to recover the missing money.
But before the case could go forward, Mr. Nasheed’s opponents mounted demonstrations in Malé, the capital of the Maldives, over his order to arrest a judge. Protesters gathered outside the defense headquarters, where Mr. Nasheed had taken refuge, and he faced a mutiny by some in the police and military. Believing that protesters would soon overrun the building, he resigned.
“If I didn’t accept their terms, and resign, in fact what they were saying was that the doors would be opened for the mob to enter,” he said. “I thought it was best to relent and bring some calmness to the situation.”
His successor as president, Mohammed Waheed Hassan, a Yameen ally, quickly halted the court action.
Last year, Mr. Nasheed was convicted of terrorism and sentenced to 13 years in prison for having arrested the judge, which the court construed as an abduction under the country’s antiterrorism law. Two of the three judges at Mr. Nasheed’s trial were prosecution witnesses in the case. He was not allowed to present witnesses of his own.
Amnesty International denounced the trial as “a travesty,” and Secretary of State John Kerry called his imprisonment “an injustice.”
Facing intense international pressure, Mr. Yameen allowed his rival to leave prison and go to Britain in January for back surgery. Under the deal, Mr. Nasheed was expected to return after the operation and complete his prison term.
But Mr. Nasheed said he was receiving nonsurgical treatment instead. Britain granted him political asylum in May, and he said he did not intend to return the Maldives while Mr. Yameen was in power.
He said he was helping organize the country’s factionalized opposition into a coalition that could oust Mr. Yameen.
“It doesn’t do anyone any good to have me in jail,” he said.