The UN is bracing for a mass movement of 900,000 people who are expected to flee if the government launches a large-scale offensive in Syria's last rebel-held region of Idlib.
Cavusoglu on Friday said Turkey was ready to cooperate with anyone in the fight against terror groups in Syria, but criticised the Damascus regime for using the presence of jihadists groups to legitimise a possible operation in Idlib. Those views echoed statements made by Russian President Vladimir Putin in Berlin in August, who said: "We need to strengthen the humanitarian effort in the Syrian conflict".
The presidents of Turkey, Iran and Russian Federation met in Tehran last week but did not agree a ceasefire that would prevent an expected offensive. It is up to parties to the conflict and the Governments that support such parties to protect the civilian population in Idlib and across Syria.
Still, a meeting of presidential aides from Russia, Germany, Turkey and France devoted to Syria will take place in Istanbul on Friday.
The Assad regime has twice been targeted by United States air and missile strikes after previous alleged chemical attacks, and U.S. officials have in recent days said additional action would follow if Assad uses the banned weapons in rebel-held Idlib.
"Should we see three million of the people headed to the Turkish border, this is a scenario that by far outweighs the capacity of all the humanitarian organizations put together", he said.
It came amid rising global concern that a looming Syrian government assault against rebels in the northwest province of Idlib would be a "bloodbath". "We will continue our efforts on worldwide platforms as well", he said.
"The safety and protection of some 2.9mn civilians residing in Idlib and surrounding areas is at risk".
However last week Erdogan and Putin failed to agree on a ceasefire at a three-way summit in Tehran which also involved Iranian President Hassan Rouhani.
German Foreign Minister Maas warned that a large-scale military offensive by the Syrian regime would lead to a humanitarian disaster in Idlib, which is home to more than 3 million civilians.
The Turkish military, which is deployed across an arc of northwest Syria near Idlib with its rebel allies, has also set up 12 observation posts around Idlib this year.
In the provincial capital, Idlib city, and in towns including Kafranbel, Dana, Azaz, Maaret al-Numan and al-Bab, demonstrators filled the streets after noon prayers and chanted against Assad, raising the tri-color green, white and black flag that has become the banner of Syria's 2011 uprising, activists said. The U.N. has warned that a battle will spark a humanitarian catastrophe. "We have seen it in use before, and we strongly advise that it does not happen in this enclosed area, where the population has, I think, nearly doubled by the influx of evacuees and IDPs from other parts of the country".