Yameen came to power in 2013 in a disputed election that opponents say was rigged. Since then, he has been accused of eroding democracy, cracking down on dissent and jailing opposition leaders.

In 2016, the Maldives withdrew from the UK Commonwealth after the association of former British colonies threatened to suspend it for chipping away at democratic institutions.

To the alarm of some opposition figures, Yameen courted investment from China and Saudi Arabia -- his last visit to Beijing was in December.

Mohamed Nasheed, who became the country's first democratically elected President in 2009 and achieved worldwide renown for highlighting the effect of global warming on the archipelago, was imprisoned in 2015 on terrorism charges that his supporters say were spurious.

Nasheed was allowed to leave prison a year later to seek medical treatment abroad, and was granted asylum in Britain. He hoped to challenge Yameen in presidential elections later this year, and was in the Sri Lankan capital, Colombo, when the Supreme Court delivered the ruling that touched off the latest crisis.

What's happening now?

The simmering political crisis came to a head last week when the Supreme Court, in an unexpected ruling, ordered the release of nine dissidents and the reinstatement of 12 legislators who were fired for abandoning Yameen's party. The ruling would have given the opposition a majority in the country's legislative assembly.

Yameen refused to comply, and instead dispatched the military to the Supreme Court in the capital, Male, on Monday.

Security forces "blockaded and locked the Supreme Court building from outside and hence the justices are without any food," Maldives' former Attorney General Husnu Al Suood tweeted.

Police also detained Yameen's estranged half-brother and former president Maumoon Abdul Gayoom, who ruled the country for 30 years until the transition to democracy. The pair fell out in 2016, journalist Mohamed Junayd said, and last year he joined forces with Nasheed to form a new opposition coalition.

Gayoom was arrested along with his son-in-law, Mohamed Nadheem, early on Tuesday morning in what the Maldivian opposition have called "blatantly trumped up charges of bribery."

In a televised address to the nation, Yameen claimed he had acted to prevent a coup, Reuters reported.

The President's office insisted that while the state of emergency imposed certain restrictions, no curfew would be put in place. "During this time, though certain rights will be restricted, general movements, services and businesses will not be affected," it said in a statement.

What's been the reaction?

The two former Presidents have urged India to intervene to force Yameen to release the judges and other political prisoners. Nasheed urged India to deploy a "physical presence" in the archipelago.

India -- which rarely intervenes in foreign countries -- helped put down an attempted coup in the Maldives in the 1980s.

In a statement, India encouraged its neighbor to abide by the rule of law. "In the spirit of democracy and rule of law, it is imperative for all organs of the Government of Maldives to respect and abide by the order of the (Supreme) court," the statement said.

The US issued a stern criticism of the President's actions. "President Yameen has systematically alienated his coalition, jailed or exiled every major opposition political figure, deprived elected members of parliament of their right to represent their voters in the legislature, revised laws to erode human rights... and weakened the institutions of government," the State Department said in a statement.

China, which has been vying with India for influence in the region, said the crisis should be resolved internally, Reuters reported.

Yameen appears to be enjoy the support of the army, at least for now. State television showed several police officers and soldiers promising to sacrifice their lives "in the defense of the lawful government" on Sunday, Reuters said.

Is it safe for tourists?

Situated to the southwest of India and Sri Lanka, the Maldives are hugely popular as a tourist destination, especially for Chinese visitors.

Almost 1.4 million tourists from across the world visited the Maldives in 2017, according to government statistics, including hundreds of thousands from China and the United Kingdom.

The Maldives government released a statement Tuesday through its Ministry of Foreign Affairs, reassuring tourists that the situation remained calm and would not affect tourism.

"All tourism related businesses will be operating as usual and the situation of the Maldives remains stable," the release said. "The state of Emergency does not force any restrictions on traveling to the Maldives or within the Maldives."

China issued a travel warning for the island chain ahead of the Lunar New Year, which begins February 16 and is China's peak travel season.

"We suggest the Chinese tourists who plan to travel to Maldives should not go there before the situation calms down," a Ministry of Foreign Affairs spokesman said Monday.

India and the United Kingdom also issued travel warnings for archipelago.