Maldives President Abdulla Yameen declared a 15-day state of emergency in the honeymoon islands, before heavily armed troops stormed the country's top court and arrested the Chief Justice Abdulla Saeed. Earlier, a former president was also arrested in a deepening political crisis.
The tiny tourist archipelago has been plunged into chaos recently, with the president pitted against the Supreme Court after he refused to comply with its Thursday order to release nine political dissidents.
The tense standoff comes amid a years-long government crackdown on dissent that has battered the image of the upmarket holiday paradise, with the president jailing almost all the political opposition since he came to power in 2013.
Maldives police arrested Yameen's estranged half-brother and former president Maumoon Abdul Gayoom, who had sided with the main opposition and was campaigning against him.
The 80-year-old, who was president for 30 years until the country's first democratic elections in 2008, was taken away from his home in the capital Male around midnight, according to a tweet from his daughter Yumna Maumoon.
Shortly before he was taken in by the police, Gayoom also recorded a video message posted on Twitter to his supporters.
"I have not done anything to be arrested," he said. "I urge you to remain steadfast in your resolve too. We will not give up on the reform work we are doing."
Chief Justice and another judge, Ali Hameed, were arrested in the early hours of Tuesday morning "for an investigation", police said.
Hundreds of people had gathered outside the courts complex and police used pepper spray to disperse the crowds.
The court's shock move on Thursday had also ordered the government to restore the seats of 12 legislators sacked for defecting from Yameen's party, giving the opposition the majority in the assembly, meaning they could potentially impeach the president.
A defiant government — which has since ordered police and troops to resist any attempt to arrest or impeach Yameen — said the court was not above the law.
"The Supreme Court ruling stands in defiance of the highest authority in the country: the constitution," government spokesman Ibrahim Hussain Shihab said in a statement.
"The Supreme Court must remember that it too is bound by law."
He said the government would "facilitate calm" and ensure the safety of all citizens and tourists "throughout this unusual period.
The government of India said in an official statement, "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 apex court. We also hope that the safety and security of the Indian expatriates in the Maldives will be ensured by the Maldivian authorities under all circumstances."