Sri Lanka's government is in crisis and its peace process in danger after the country's president deployed troops around the capital and fired three key ministers.
The ministers were trying to coax Tamil rebels back into talks to end a 20-year civil war.
President Ms Chandrika Kumaratunga - who is commander of the armed forces and has wide executive authority under the constitution - made the surprise power grab against her political rival, Prime Minister Mr Ranil Wickremesinghe, while he was in Washington to meet US President George Bush.
Defence Minister Mr Tilak Marapone, Interior Minister Mr John Amaratunga and Information Minister Mr Imthiaz Bakeer Markar were removed from their posts. Three top aides to the ministers also were fired.
Ms Kumaratunga has been severely critical of how Mr Wickremesinghe has handled peace efforts with the Tamil Tiger rebels, arguing that his government has given too many concessions without ensuring that the Tigers abandon their armed struggle.
However, Mr Wickremesinghe remains prime minister.
Troops were sent to the state TV and radio stations, and to a main power plant, shortly after announcements that the ministers had been fired.
"Several platoons have been deployed to prevent any unwanted incidents and to maintain law and order," a military spokesman said.
President Kumaratunga's office said in statement that the move to sack the ministers was "taken after careful consideration in order to prevent further deterioration of the security situation in the country".
Mr Wickremesinghe and other Sri Lankan officials were holding an emergency meeting in the US capital today.