Rebels downed a helicopter in fierce fighting yesterday with troops seeking to retake a key Syrian town, a watchdog said, as peace envoy Lakhdar Brahimi warned the conflict risks setting the region ablaze. The battle for the Damascus-Aleppo highway raged around the northwestern town of Maaret al-Numan even as Brahimi appeared to have won tentative support for a ceasefire plan. The UN and Arab League envoy warned of the conflict spreading as he visited neighbouring Lebanon. "This crisis cannot remain confined within Syrian territory," Brahimi said in Beirut. "Either it is solved, or it gets worse ... and sets [the region] ablaze. A truce for [the Muslim holiday of] Eid al-Adha would be a microscopic step on the road to solving the Syria crisis." Brahimi called this week for a temporary ceasefire during the four-day Eid holiday starting on October 26. Damascus says it is prepared to discuss the truce proposal with Brahimi while the exiled opposition says it would welcome any ceasefire but insists the ball is in the government's court to halt its daily bombardments. On the battlefront, rebels shot down a helicopter gunship in the northwest as the army fought to recapture the strategic town of Maaret al-Numan, said the Syrian Observatory for Human Rights.