Syria's army captured an airbase in eastern Aleppo from ISIS Saturday, after more than two months of fierce clashes, a military source and activists said.
The Jarrah airbase had been under ISIS control since January 2014, when the extremists seized it from rebels who had captured it a year earlier.
"Regime forces took control of the Jarrah military airport after heavy fighting," said Rami Abdel Rahman, director of the Syrian Observatory for Human Rights activist group.
"The majority of the extremists have withdrawn, and regime forces are carrying out clearing operations in the airport and engaged in limited clashes with remaining ISIS elements," he added.
Syria's army launched an offensive against ISIS in eastern Aleppo province in mid-January, backed by ally Russia.
So far it has taken control of more than 170 villages and towns in the area, according to the Britain-based activist group.
A military source, speaking on condition of anonymity, also confirmed the capture of the military base.
"The Syrian army has completed its capture of Jarrah airport and a number of the surrounding villages," he told AFP.
"It will continue its advances into the areas held by the terrorist organisation and... expand the areas it controls in eastern Aleppo province," he added.
The next key target for government forces in the area will likely be the town of Maskana, on the edge of Lake Assad.
Syria's army is just one of the forces battling ISIS in the country.
An alliance of Syrian Kurds and Arabs is also fighting the group further east, in Raqa province, with support from the U.S.-led coalition.
More than 320,000 people have been killed in Syria since the conflict began in March 2011 with anti-government protests