Syria rebels were early Wednesday battling regime troops inside the Minnigh military airport in the north of the country for the first time, the Syrian Observatory for Human Rights said.
"The rebels, who have laid siege to the airport for months now, entered it for the first time around dawn," Observatory director Rami Abdel Rahman told AFP.
"Heavy fighting is still taking place this morning inside the grounds of the airport," he said.
The rebels on Tuesday took a key military position outside the airport, in Aleppo province, which allowed them to launch a raid on the facility.
A group of regime-allied fighters who attempted to reach the airport to boost government troops there were intercepted by Kurdish fighters who killed nine of them, the Observatory said.
Rebel fighters have tried multiple times to take the Minnigh airport, a key military facility in Aleppo province.
Since the beginning of the year, rebel forces have been fighting what they call the "battle of the airports in Aleppo" in a bid to deprive the regime of a key supply route.
Rebels have set their sights on the Aleppo international airport, along with the Jarrah, Kwiyres, Minnigh and Nayrab military airports. They took the Jarrah military airport on February 12.