Security forces in the Maldivian capital, Male, have used batons and fired teargas to break up a rally in support of former President Mohammed Nasheed.
Dozens of his supporters were wounded.
Mr Nasheed, who resigned on Tuesday, accused vice president Mohammed Waheed Hassan of being part of the coup. Mr Hassan who is now president, denies this.
Mr Nasheed left office following pressure over the arrest of a top judge.
He says he was forced out of power at gunpoint. He did not elaborate on who held him at gunpoint, but one aide says he was hustled out by the military.
That has prompted the clashes between police and the former president's supporters.
The BBC reports Mr Nasheed's whereabouts over the past 24 hours have been unclear at times.
Mr Nasheed was elected in 2008, defeating President Maumoon Abdul Gayoom, who had ruled for more than 30 years.