President Mahinda Rajapaksa of Sri Lanka is dissolving parliament, clearing the way for early elections.
A senior official was quoted as saying the dissolution took effect at midnight on Tuesday.
Mr Rajapaksa won a second term in office by a large margin last month, but the outcome was rejected by his main rival, General Sarath Fonseka.
General Fonseka was detained by security forces on Monday.
Opposition politicians say the government is engaged in a witch-hunt and called for protests on Wednesday against the arrest.
Announcing the dissolution of parliament, presidential spokesman Lucien Rajakarunanayake said it was up to the elections commissioner to decide dates for the parliamentary vote.
Parliament was elected in 2004 and could have continued until April.
President Rajapaksa's win in January followed the ending of a long civil war against Tamil Tiger rebels.
