Ukrainian MPs have voted to oust President Viktor Yanukovych and hold early presidential elections on 25 May.
The vote came after police stopped guarding presidential buildings allowing protesters in and parliament appointed high-level officials.
Mr Yanukovych described events as a "coup" and vowed not to stand down.
Also on Saturday afternoon, prominent opposition leader Yulia Tymoshenko was released from detention, hours after parliament authorised the move.
A BBC correspondent saw Tymoshenko driven away in a car after leaving a hospital in the eastern city of Kharkiv where she was being held under prison guard.