At least 40 Syrian troops were killed on Tuesday as rebel forces overran most of the military base near Aleppo's international airport, the opposition Syrian Observatory for Human Rights said, dpa reports.
The remaining troops were dug into a section of the base adjoining the Nairab military airport, the Britain-based group said.
Two opposition fighters were also confirmed dead and dozens injured, some seriously.
Earlier Tuesday rebels from Islamist brigades claimed control of Jarrah air base on the outskirts of Aleppo, Syria's largest city, after a day of heavy fighting.
According to the Observatory, which collates reports from activists around Syria, the base still contained dozens of MiG-17 and Sukhoi L39 fighter jets.
In New York, UN High Commissioner for Human Rights Navi Pillay said almost 70,000 people had been killed in the conflict, which enters its third year next month.