Maldives President Abdulla Yameen Gayoom has declared a state of emergency, giving sweeping powers to security forces to arrest suspects ahead of a major anti-government protest rally, his spokesman said.
"Maldives declares state of emergency for a period of 30 days starting 12pm [07:00 GMT] Wednesday," the presidential spokesman Muaz Ali tweeted on Wednesday.
Gayoom said on Tuesday he would take all steps to ensure the safety of his people, a day after an explosive device was found near his official residence.
In his speech to the nation he said an explosion last month on his speedboat was "an act of greed to attain power", an apparent reference to his vice president, who is being held for questioning over the alleged assassination attempt.
The FBI, which investigated the incident at the Maldives' request, said on Saturday it found no evidence a bomb had caused explosion on the boat.
The government said Gayoom was not sitting in his usual seat on the boat and thus was not hurt by the blast, which injured his wife, an aide, and a bodyguard.
Vice President Ahmed Adeeb was among nine people arrested on suspicion of involvement in the boat explosion. The Maldives Constitution provides for the vice president to assume power if the president dies or is incapacitated.
Maldives is an Indian Ocean archipelago with 350,000 people, mostly Sunni Muslims, and is known for its beaches and luxury resorts.
It has had a difficult transition to democracy since holding its first multiparty election in 2008, with the first democratically elected leader being jailed for 13 years under the country's terrorism law.
The trial was criticised both locally and internationally for an apparent lack of due process.