MOSCOW (AP) — Turkey's Foreign Minister has warned against a possible Syrian government offensive on the last remaining opposition stronghold.

Mevlut Cavusoglu, who was in Moscow on Friday for talks with Russian counterpart Sergey Lavrov, said that Russia and Turkey should work to separate opposition groups from "terrorists" in the northwestern province of Idlib. He warned against an offensive there, saying that it will cause a "humanitarian catastrophe."

Lavrov, however, indicated that Moscow is losing patience with the militants, who often target government positions from there.

Russia is a key backer of Syrian President Bashar Assad, while Turkey supports some of the opposition groups along its border with Syria. Turkey, Russia and Iran have mediated cease-fire deals in several areas in Syria, including Idlib.