"We had to find out why", Yameen said. He also labeled the original court ruling a coup and a plot.
On Monday, he ordered the arrest of his estranged half-brother and former president Maumoon Abdul Gayoom, who had sided with the main opposition.
The emergency declaration gives sweeping powers to security forces to arrest and detain individuals, curtails the powers of the judiciary and bars parliament from impeaching Yameen.
On 1 February 2018, the Supreme Court ordered the release of nine political opponents of President Yameen, including former President Mohamed Nasheed, who is living in exile.
Since Thursday, global actors, including the United Nations and countries such as India, the US and the U.K. have been urging the Male government to respect the ruling.
Yameen, in an address to his nation which was televised across the island country, said the recent Supreme Court order to release top opposition leaders was "shocking" and this had threatened to "cripple" the functioning of the state.More news: Paypal Holdings Inc (PYPL) Expected to Post Earnings of $0.52 Per Share
More news: Kelly says Trump likely won't extend DACA deadline
More news: SpaceX's New Rocket Ready for First Flight
His lawyer, Maumoon Hameed, said Gayoom faced charges including bribery and attempting to overthrow the government.
On Monday, the tension escalated when Maldives National Defense Forces reportedly broke into the Supreme Court in the capital city of Male. However, the Supreme Court cited that more than six months after its ruling, the Government and the Parliament have failed to adopt necessary legislation, while at the same time 12 legislators who had defected from the ruling Progressive Party of the Maldives (PPM) were unseated. Tourism now dominates the economy, with wealthy foreigners flown to hyper-expensive resort islands.
The Attorney General on Sunday instructed the police and troops not to obey the court's order, though the court maintained that there were "no legitimate reasons" to obstruct authorities from implementing it. The two men are now political enemies. He has jailed nearly all the political opposition.
Nasheed was jailed in 2015 after he was convicted on a terrorism charge widely seen as politically motivated. The Court ruled that their trials had been conducted "based on political motivations; and in violation of the Constitution and worldwide human rights covenants acceded by the Maldives" and ordered their release until retrials and judgement in accordance with the law have been conducted.
Nasheed said after last week's ruling that he would mount a fresh challenge for the presidency later this year. China urged people to avoid travel there and the others told citizens to be cautious.
In 1988, Sri Lankan militants working for a Maldivian businessman tried to take control of the country and seized many government buildings.