Turkey's top diplomat says an agreement reached with Russia over the northwestern Syrian province of Idlib ensures the continuity of Syria's moderate opposition.

Speaking on Tuesday, Foreign Minister Mevlut Cavusoglu said the agreement reached a day earlier would allow civilians and anti-government rebels, backed by Turkey, to remain in a demilitarized zone and "retain light arms."

The minister said the demilitarized zone, to be established by Oct. 15 and be 15-20 kilometers (9-12 miles) deep, would be cleared of "radicals" and heavy weapons, such as tanks and rocket launchers.

Without the agreement, "there would have been no opposition left," calling it crucial for a lasting political solution.

Cavusoglu also said Turkey would need to dispatch more troops to patrol the area, along with Russia, while also retaining its 12 observation posts.

Syria's opposition says it is better off in the wake of a Turkey-Russia deal on a demilitarized zone around Idlib province compared to periods following the defeat of rebels in other parts of the country.

Opposition figures said Tuesday the deal will spare Idlib a government offensive, while a pro-government newspaper said state institutions will return to Idlib before the end of 2018.

The government has vowed to eventually regain control of all Syrian territories.

After weeks of massing troops around Idlib, the last rebel-held stronghold in Syria, the leaders of Russia and Turkey agreed on Monday to establish a demilitarized zone around the province.

The move spared the province that is home to some 3 million people and 60,000 insurgents a fate similar to other areas captured by troops earlier this year.