The commander of Syria’s main Western-backed rebel group has urged all opposition fighters to join ranks in the struggle against President Bashar Assad’s forces, pledging to do everything he can to stave off rebel infighting.

In remarks broadcast Friday by a pan-Arab satellite television Al-Arabiya, Gen. Salim Idris said all rebels in Syria who believe in the “goals of the revolution” are “our brothers.” Idris spoke after a meeting late Thursday in Istanbul with U.S. Ambassador to Syria Robert Ford.

His comments suggested he was trying to limit the damage from deadly infighting among moderate and extremist rebel factions ahead of a peace conference for Syria scheduled to be held in Switzerland in January.