Syrian rebels have been targeting the airforce, triggering counterattacks and prompting fresh waves of refugees. The new UN-Arab League envoy, Lakhtar Brahimi, will now try to defuse the situation.
Syrian rebels said they had attacked another military airport on Saturday and claimed to have captured more ground-to-air missiles, which they could use to shoot down military aircraft.
According to the London-based Syrian Observatory for Human Rights, rebels captured the main air defense building in Albu Kamal, on the Iraqi border. In an attack on the military airport in Kouriss, in the northern province of Aleppo, rebels claim to have destroyed three jets, bringing to a dozen the number of aircraft destroyed in recent days.
State-run media, meanwhile, have reported that government forces have launched a counterattack against "terrorists" on the outskirts of Aleppo and around military bases.
News out of Syria cannot be independently verified, as the government bans journalists from travelling in the country.
President Bashar Assad's forces have conducted numerous air strikes on civilians in rebel-held parts of the country such as Azaz and Anadan, leading to residents fleeing to safety in Turkey, which has taken in an estimated 80,000 refugees since the conflict began almost 18 months ago.
Turkish Prime Minister Recep Tayyip Erdogan has again urged the UN Security Council to approve a resolution allowing for the creation of "safe zones" for refugees inside Syria.
But so far no nation has indicated a willingness to commit the military forces needed to secure such zones.
On Saturday, Germany took over the rotating presidency of the UN Security Council for one month. Foreign Minister Guido Westerwelle promised to push the Council to further isolate the Syrian regime.
Also on Saturday, Algerian diplomat Lakhdar Brahimi formally began his mission as the UN-Arab League special envoy for Syria.
He was appointed after his predecessor, Kofi Annan, stepped down expressing his frustration over failed attempts to find ways to defuse the conflict.
Brahimi now plans to visit Syria within the coming weeks and hold talks in Cairo with Arab League officials.
rg/mkg (Reuters, AFP, dpa)