A statement posted on the rebel-affiliated channel on Friday said: “Our forces have begun entering the city of Aleppo”.
Earlier, the monitoring group Syrian Observatory for Human Rights (SOHR), which uses a network of sources on the ground in Syria, reported that Syrian and Russian planes carried out 23 air strikes on the Aleppo region on Friday.
The SOHR said 255 people, mostly combatants, had been killed in the fighting, the deadliest between rebels and pro-government forces in Syria for years.
It said opposition forces had taken control of more than 50 towns and villages since Wednesday.
Fighting which had raged since the civil war began in Syria in 2011 had largely wound down by 2020, when Turkey and Russia – Syria’s key ally – brokered a ceasefire to halt a push by the government to retake Idlib.
That led to an extended lull in violence, but sporadic clashes, air strikes and shelling continued.
Idlib is the last remaining opposition stronghold and is home to more than four million people, many of whom have been displaced during the conflict and are living in dire conditions.