SYRIAN rebels have launched a counteroffensive in the northern city of Aleppo, recapturing a base near its international airport hours after the army had advanced into the area, activists say. Saturday's fighting came as the main Western-backed opposition group was to begin a two-day meeting in Istanbul to decide whether they will attend a proposed peace conference the US and Russia are trying to convene in Geneva. The Syrian National Coalition has demanded that President Bashar Assad step down in any transitional Syrian government as a condition for its going to Geneva. Syrian officials say Assad will stay in his post at least until his terms ends in 2014 and that he may run for re-election. In Cairo, Arab League Secretary-General Nabil Elaraby told reporters upon arrival from Geneva that the UN-Arab League's top envoy to Syria, Lakhdar Brahimi, will hold a new meeting in early December with concerned parties to decide on a new date and the attendees of the Geneva conference. "We were saddened and depressed because of the failure of the latest meetings to decide on a date and participants for the conference," Elaraby said, referring to a meeting in Geneva earlier this week that many had hoped would call for holding the talks later this month. The League had wanted the peace conference to lead to a ceasefire and secure means to deliver humanitarian aid to Syrians, Elaraby added. In Aleppo, rebels were able to fully recapture the military base of "Brigade 80" after government troops seized parts of it early on Friday, the Britain-based Syrian Observatory for Human Rights and the Aleppo Media Centre said. The main job of "Brigade 80" was to protect the government-held Aleppo International Airport, which has been closed due to fighting for almost a year. Rebels captured the base in February and now government troops are trying to get it back. The Observatory said 40 rebels and more than 20 troops were killed in the latest fighting, which began Friday and continued early Saturday. Syria's state-run news agency SANA said a rocket fired by opposition fighters hit near a health centre in Aleppo's Ashrafieh neighbourhood, killing six children and wounding six others.