Syrian opposition fighters said they had attacked another military airport on Saturday and claimed to have captured more ground-to-air missiles, as the new UN-Arab League envoy formally began his mission to help end the 18-month conflict in the country, dpa reported. Activists said opposition fighters attacked a military airport in Kouriss, in the northern province of Aleppo, and managed to destroy three jets. Two other airports were attacked in recent days in the province of Idlib. Activist Bassam al-Halabi told dpa that the area, which includes several military bases, continued to be heavily shelled by government forces. Meanwhile, Turkish Prime Minister Recep Tayyip Erdogan urged the UN Security Council to approve a resolution allowing for the creation of a buffer-zone to protect refugees inside Syria. Syrian-Turkish relations have deteriorated since the conflict in Syria began last year, with Turkey now hosting some 80,000 Syrian refugees. In other developments, video footage posted online showed opposition fighters in the east capturing Cobra ground-to-air missiles in a military air base in the Abu Kamal region, near the Iraqi-Syrian border. Opposition fighters also claimed to have captured 50 government soldiers in the base after killing their commander. The London-based Syrian Observatory for Human Rights, an opposition group, said Friday's death toll had reached 150 across Syria. Meanwhile, Algerian diplomat Lakhdar Brahimi formally began his mission, after his predecessor, Kofi Annan, stepped down. Brahimi plans to visit Syria within the coming few weeks and hold talks in Cairo with Arab League officials.