Maldives police have arrested Vice President Ahmed Adeeb on suspicion he is linked to last month's assassination attempt against President Abdulla Yameen.
Home Minister Umar Naseer posted on his Twitter account that Adeeb has been charged with "high treason" and is being held in Dhoonidhoo detention center.
President Yameen was not harmed in the September 28 blast on his speedboat. But his wife and two others were wounded.
Officials initially blamed the explosion on a mechanical problem, but later said forensics experts found evidence that indicated it was an attempt on the president's life.
The Maldives is a world famous tourist site, but has been shaken by the recent arrest and trial of former President Mohamed Nasheed. A court sentenced him to 13 years in prison for ordering the arrest of an allegedly corrupt judge when Nasheed was president three years ago.
The United Nations has ruled that the trial was illegal and ordered Nasheed's release.