Free Syrian Army fighters run for cover as a tank shell explodes on a wall in the Ain Tarma neighborhood of Damascus on Jan 30. [Photo/Agencies]

It added that a military unit, which succeeded earlier to dislodge rebels from towns near Aleppo, entered the town of Hasel on Tuesday, some 5 km from the airport and the adjacent airbase of Nairab, in a bid to secure the vicinity of both airports.

Meanwhile, local reports said clashes were still raging at the Brigade 80 base in Aleppo after it was overrun by rebels last week.

The base was responsible for providing protection to the international airport and Nairab airfield.

The rebels have intensified their attacks recently in a bid to take control over the airports and military airfields in the country.

The area has been under rebel control for months, activists said.

The UN recently said that 70,000 have been killed since the anti-government protests began in March 2011 in Syria. UN humanitarian Chief Valerie Amos said the number of those who have fled to neighboring countries in the last two months has reached 250, 000.