Turkish Foreign Minister Mevlut Cavusoglu warned Friday that seeking a military solution in Syria's last rebel-held province of Idlib would lead to disaster.
"A military solution there will cause catastrophe," Cavusoglu said at a press conference in Moscow with Russian counterpart Sergei Lavrov.
"Not only for the Idlib region but for the future of Syria, it will cause catastrophe and the clashes may last a long time."
He cited the risk to the region's large civilian population.
"Civilians will be harmed. Where will the 3.5 million civilians go?"
Speculation is increasing that there could be a Russian-backed government assault on the northwestern province, home to Syria's last major rebel stronghold.
Cavusoglu said that Turkey nevertheless considers "it is very important that those radical groups, terrorists are rendered ineffective".
"It's also important for Turkey because they are on the other side of our border. They pose a threat to us first."
Russian President Vladimir Putin was set to meet with the Turkish and Russian defence and foreign ministers on Friday, Kremlin spokesman Dmitry Peskov said, quoted by Interfax news agency.
The jihadist Hayat Tahrir al-Sham (HTS) alliance controls around 60 percent of Idlib, which borders Turkey, while other Turkey-supported rebel groups hold most of the rest.
Idlib is one of the so-called "de-escalation" zones set up by Russia, Turkey and Iran last year.
Analysts say any regime offensive will probably be limited to a small area of Idlib, with a deal between Russia and Turkey likely to determine the fate of the rest of the province.
Russian Foreign Minister Lavrov said Friday that the situation was "multi-faceted" and called for separating out "the healthy opposition from terrorist structures."
"When the de-escalation zone was created in Idlib, no one proposed using it for terrorists to hide behind the civilian population like a human shield.
"Especially as they aren't just lying low there. Raids constantly come from there and firing on the positions of the Syrian army."
He said he was sure Turkish and Russian presidents would "talk in detail on this topic."