Opposing fighters of Al-Assad regime attacked a sprawling air base in northern Syria on Wednesday as the opposition expanded its offensive on military airports. The Britain-based Syrian Observatory for Human Rights said the opposing fighters assault on the Taftanaz base was preceded by heavy shelling of the area, and the fighters appeared to be trying to storm the facility. Observatory director Rami Abdul-Rahman described the attack as one "of the most intense" on the airfield. The Observatory said the regime's army helicopters were helping defend the airfield against the opposition assault. It added that four opposing fighters were killed in the clashes around the base and that one helicopter was hit by rebel fire.