Hundreds of rebel fighters have joined the battle for Qusayr.
The strategically important city is surrounded by government forces backed by fighters from the Lebanese armed group Hezbollah.
Brigadier General Salim Idris told Al Jazeera the revolution could be lost without immediate support from the West.
Idris says 300 of his fighters are now in Qusayr but heavily outgunned and overwhelmed by fighters from Hezbollah.
He warns the "revolution could be lost", if the West does not act quickly.
Al Jazeera's Andrew Simmons reports from the FSA command centre in Syria.