TEL RIFAT, Syria (AP) — Syria launched a ground assault Wednesday on rebel-held areas of the besieged city of Aleppo, the center of battles between government forces and opposition fighters for more than two weeks.

It was not immediately clear if the offensive was “the mother of all battles” that Syria’s state-controlled media vowed last month would take place for control of Aleppo. In recent weeks, the regime’s blistering attacks on rebel positions seem to have slowly chipped away at the opposition’s grip on its strongholds in the country’s largest city.