Al-Qaida's Syrian affiliate and its allies seized the last regime-held military base in northwestern Idlib province on Wednesday, in the latest setback for President Bashar al-Assad's forces.
Al-Nusra Front and a coalition of mostly Islamist groups captured the Abu Duhur military airport after a siege that lasted two years, the Syrian Observatory for Human Rights monitor said.
"After a violent attack that had been taking place since Monday, Al-Nusra Front and some Islamist factions control all of the Abu Duhur military airport," the Britain-based Observatory said.
The attacking force began to enter the base on Tuesday night.
Observatory chief Rami Abdel Rahman said the forces appeared to have taken advantage of a massive sandstorm that blanketed much of the Middle East and made it difficult for regime aircraft to carry out strikes.