Syrian pro-government forces have taken full control of the strategic town of Qusair, state TV and the rebels say.
The town, near the Lebanese border, has been the centre of fighting for more than two weeks between rebels and Syrian troops backed by fighters from the Lebanese militant group Hezbollah.
Syrian state TV said a large number of rebels had died and many had surrendered.
The rebels said they withdrew overnight in the face of a massive assault.
The military leader of the main rebel umbrella group, the Free Syrian Army, had earlier said his fighters were prepared to take the conflict inside Lebanon in pursuit of Hezbollah fighters.