The Kyrgyz parliament has appointed opposition deputy Ishenbai Kadyrbekov as acting president of the Central Asian country after days of violent street protests.
The opposition in the former Soviet republic earlier seized control of the capital, Bishkek, after overrunning the president's palace.
Demonstrations were stepped up after recent parliamentary elections, which the opposition said were rigged.
An unconfirmed report by Interfax news agency said President Askar Akayev and his family have left the city by helicopter.
It is also reported that Mr Akayev and the Kyrgyzstan Prime Minister, Nikolai Tanayev, have resigned.
Kyrgyzstan's Supreme Court has now annulled February's controversial elections and recognised the former parliament as the legitimate legislature.
Earlier, opposition protestors broke police lines and stormed the government buildings, known as the White House.
Several thousand protestors marched to the government building, demanding the resignation of the president.