Police in the Maldives have arrested an opposition party leader on a charge of plotting to overthrow the government, a move the joint opposition condemned on Friday as intensifying a crackdown on political opponents.

Jumhooree Party leader and lawmaker Qasim Ibrahim had signed an agreement with others last month to try to restore democracy in the archipelago nation, and the joint opposition said his arrest was aimed at obstructing the work of the alliance, which it said has threatened the power of President Yameen Abdul Gayoom.

Mr. Qasim was arrested on Thursday evening on the charges of “attempting to influence no confidence motions against the Speaker of Parliament” and “plotting to overthrow the government,” according to the joint opposition’s statement.

The arrest of the tourism tycoon came days after the government defeated a no-confidence motion against the speaker and thereby prevented the opposition bid to take control of Parliament.

The opposition says the charges are “trumped-up” and demonstrate the willingness of Gayoom’s government to “subvert state institutions in order to pursue and persecute anyone to who attempts to hold him accountable.”

Spokesmen for the government and for police did not answer phone calls on Friday seeking comment.

The opposition alliance includes the Maldives’ first democratically elected leader Mohamed Nasheed, its former strongman leader Maumoon Abdul Gayoom, Qasim and another political party.

Mr. Yameen is a half-brother of Mr. Maumoon and became President in 2013 by defeating Nasheed. Since then he has been accused of using the judiciary, police and bureaucracy to crack down on opponents.

Mr. Nasheed, a vice president, a defense minister and another political party leader have been given lengthy prison sentences after trials on terrorism charges that were criticized for lack of due process.

The government also tightly controls public gatherings and recently enacted an anti-defamation law with hefty fines and jail terms for journalists and social media users.