"Government forces took control of the strategic Safira city after days of clashes and heavy shelling," the Britain-based Syrian Observatory for Human Rights said.
The Observatory, which has a network of sources across Syria, did not give further details and there was no immediate comment on the reports in Syrian state media.
The Organisation for the Prohibition of Chemical Weapons (OPCW), which has teams in Syria to eliminate the country's chemical weapons, has said its teams were unable to reach two sites for inspection because they were too dangerous.
The OPCW has not said which locations it had been unable to inspect, but a source briefed on their operations said one was at Safira, which is southeast of Aleppo.
The chemical weapons site itself has been under government control but emptied of equipment because of fighting nearby, the OPCW said.