Government forces killed "hundreds of ISIS terrorists and destroyed their dens and cells with all weapons inside," state news agency SANA reported. A major troop buildup has been in the works in the area since last month.
"The regime has been fighting since the end of September to break the siege," said Rami Abdurrahman, the head of London-based Syrian Observatory for Human Rights. "Taking this airport back from siege means they can advance to ISIS areas. They can use it to shell areas around Aleppo."
Since breaking the ISIS siege at the airport, the Syrian army has made advances in Aleppo, according to SANA and an opposition military adviser familiar with the area.
"The army's air force destroyed positions and vehicles for ISIS terrorists in (a number of villages in) the eastern countryside of Aleppo province," SANA reported Wednesday, citing a military source.
Col. Abdelsalam Al-Hamidi, a Free Syrian Army adviser who's based in Turkey but remains in close contact with rebel forces in Aleppo, said Syrian government forces gained ground "under the cover of the Russians, with help from Iranian and Iraqi forces."
But the opposition forces were able to stop the advance in some areas, he said, retaking territory they had lost.
"They adapted to the situation (and) were able to minimize losses, (using) camouflage and excellent maneuvers," Al-Hamidi said.
The Syrian military has been backed by Russian air power in recent weeks.
Aleppo is one of three areas the Russians seem to be focusing on
. The others are the northern province of Idlib and in Hama province, near the coast.
Iranian and Hezbollah militia also are coordinating with Syrian forces to take advantage of the air strikes in a bid to regain territory from ISIS and opposition groups.