CNN  — 

Russia and Turkey have agreed to create a demilitarized zone in Syria’s Idlib province, potentially thwarting a large-scale military operation and impending humanitarian disaster in the country’s last rebel stronghold.

Speaking alongside Russian President Vladimir Putin at talks in Sochi on Monday, Turkish President Recep Tayyip Erdogan said the creation of a 15- to 20-kilometer (approximately nine to 12 miles) demilitarized zone will prevent a “humanitarian crisis” in the northwestern province.

All heavy military equipment tanks, ground-to-air missiles and mortars of all the opposition groups will be removed by October 10, the leaders said. The zone, which will be patrolled by Turkish and Russian military units, will become operational from October 15.

Erdogan described the agreement as a “solution” to the issues in the region.

“Russia and Turkey will both have coordinated patrol activities on both sides of the border at the demilitarized zone,” Erdogan said.

“With this agreement, I believe that we will prevent a big humanitarian crisis in Idlib,” Erdogan added.

Preparations for government offensive

In recent weeks, Syrian and Russian planes have conducted scores of airstrikes in Idlib in the run-up to an anticipated offensive by Russian-backed Syrian forces to retake the last part of the country under armed opposition.

In a report Friday, Amnesty International accused the Syrian government of using outlawed cluster weapons and unguided barrel bombs in the attacks against the opposition groups.

Armed groups in Idlib province – increasingly dominated by Islamist extremists – have since early August been arresting people who promote and pursue reconciliation and surrender agreements with the Syrian regime, according to statements from members of the opposition, the armed groups themselves and an Idlib-based activist who talked to CNN last week.

Last week, UN officials said that more than 30,000 people fled the province in anticipation of the government offensive.

On Tuesday, the United Nations Special Envoy for Syria Staffan de Mistura welcomed the Russia-Turkey agreement and said that the plan should be “expeditiously” put in place. In a rare remark, the UN envoy said that “for now we are pleased.”

Syria ‘welcomes’ agreement

Speaking about the Sochi agreement Tuesday, Turkish Foreign Minister Mevlüt Cavusoglu said that civilians and opposition members would be allowed to stay in the demilitarized zone, while “terrorist groups” and heavy weapons would be removed.

“The normal light weapons in the hands of moderate opposition forces will remain,” the minister said during a press conference with his Jordanian counterpart in Ankara, adding that Turkey will send more troops and will keep its 12 observation posts in Idlib.

The Syrian government welcomed the Russian-Turkish agreement over Idlib but said it will continue its “war on terrorism until it liberates every inch of Syrian territory, whether by military operations or local reconciliation deals.”

“We welcome every initiative that stops the Syrian bloodshed,” the foreign ministry said in a statement carried by the official news agency SANA.

The agreement met with mixed reactions from some of Idlib province’s 30 million inhabitants.

Abdullah Ibrahim, who lives in the city of Andan, told CNN the agreement was “worst of the best possible options,” citing bilateral agreements that failed in the past.

“There is a great fear because Syrian regime forces and Russian forces are always violating all agreements that have been signed in the past. So this one won’t be different and (it will be) a matter of time before this agreement fails and things will be ugly again,” Ibrahim said.

Activist Zaher Abu Jaber told CNN that people living near the buffer zone are continuing to gird themselves for an onslaught.

“People are really afraid near the front lines in Southern Idlib, where these deescalation zones will be implemented. People are still digging caves and preparing for the worst, especially in the areas of Kafr Zayta and Latamneh where most of the bombing earlier this month took place. The residents don’t trust the Russians at all,” he added.

The agreement came on the same day that a Russian military aircraft was inadvertently shot down by Syrian regime antiaircraft artillery amid an Israeli attack on Syrian positions.

Kremlin press secretary Dmitry Peskov said that the downing would not affect the Sochi agreement “in any way,” adding that “this is an important, breakthrough agreement.”

The Russian Defense Ministry ruled out new military operations in Idlib province on Monday, according to Russia’s state news agency TASS. 

According to the report, Russian Defence Minister Sergei Shoigu was asked by a journalist if no more military operations were planned to be held in Idlib, to which he replied “yes.”

Shoigu reportedly added: “In the hours to come, we plan to make final agreements with them (the Turkish side) on the remaining provisions, which are stipulated in this document.”

CNN’s Sebastian Shukla, Simon Cullen, Nathan Hodge, Sara El Sirgany, Gul Tuysuz, Judith Vonberg and Tamara Qiblawi contributed to this report.