(MOSCOW) — The leaders of Russia and Turkey on Monday announced that a deep demilitarized zone will be established in Syria’s Idlib region, the last bastion of anti-government rebels where fears had been high of a devastating offensive by government forces. The zone will be established by Oct. 15 and be 15-20 kilometers (9-12 miles) deep, President Vladimir Putin said at the end of a more than three-hour meeting with Turkish President Recep Tayyip Erdogan. “I believe that with this agreement we prevented a humanitarian crisis in Idlib,” Erdogan said at a joint briefing with Putin in Sochi. The province of Idlib in the country’s northwest is the last stronghold of Syrian rebels, and Turkey has been eager to prevent a government assault. Russia has called Idlib a hotbed of terrorism and had said the Syrian government has the right to retake control of it.