Turkey's EU affairs minister warned Friday that conflict in Aleppo in neighbouring Syria could displace 1 million people.
"Without a doubt, Aleppo is not only the problem of the Middle East. A conflict that erupts there will cause 1 million more people to take to the road," Omer Celik said, according to the private Dogan news agency.
Turkey's border to Syria has been largely closed for more than a year. Last year, hundreds of thousands of refugees left Turkey for Europe, often taking risky boat trips. The country hosts more than 2 million Syrian refugees.
Rebel-held eastern Aleppo is currently under a siege, with Russia and Syrian planes pounding the area. Pro-government troops are also advancing on the opposition stronghold. Turkey is a staunch backer of rebel groups in Syria.
Prior to the war, Aleppo was Syria's most important commercial centre.
Turkey this week also warned that the battle to seize Mosul, in Iraq, from Islamic State could also create a million refugees.