A Maldives court has convicted the country's former vice president of masterminding a plot to kill the president by exploding a bomb on his speedboat last year and sentenced him to 15 years in prison.

Ahmed Adeeb must serve a total of 25 years after the same criminal court sentenced him earlier this week to 10 years for possessing firearms.

Adeeb is the fourth high profile politician to be jailed on terrorism charges since Yameen Abdul Gayoom was elected president in 2013. The South Asian country is best known for its luxury island resorts.

Adeeb's lawyers said they would appeal the sentence.

Gayoom escaped unhurt in the September blast but his wife, an aide and bodyguard were wounded.