Leder for en av de største opprørsgruppen, Tawhid, døde av skadene han fikk etter et flyangrep i Aleppo torsdag.
The death was the latest blow to rebels amid advances in recent weeks by President Bashar Assad’s forces.
A spokesman for the Tawhid Brigade, the main rebel outfit in Syria’s northern Aleppo province, says the group’s leader Abdul-Qadir Saleh died overnight.
Akram al-Halaby said on Monday that the brigade appointed Abdul-Aziz Salameh to succeed Saleh. The shelling last Thursday killed the brigade’s financial officer, Abu Tayeb, and wounded another spokesman, Saleh Anadan.
The Tawhid Brigade is one of Syria’s better-known and stronger rebel groups, with an estimated 10,000 fighters. Under Saleh’s command, they pushed into the provincial capital of Aleppo last year, seizing large sections of the city for the rebels.