Commander Nabel is a Christian who leads a local group of volunteers fighting alongside President Bashar al-Assad's forces in the war in Syria.
His fighters are camped outside Idlib, Syria's last remaining rebel stronghold.
They were expected to launch a final offensive on Idlib last month. That was postponed after a demilitarised zone was agreed.
But President Assad hasn't ruled out future military action, in his bid to restore complete control over the country.