Turkey hosts some 3.7 million Syrian refugees, the largest refugee population in the world. It fears a new wave from Idlib, where up to 3 million Syrians live in the last rebel-held swathe of territory, after Russian and Syrian government forces last month intensified their bombardment of targets in the region."Right now, 200,000 to 250,000 migrants are moving towards our borders. We are trying to prevent them with some measures, but it's not easy. It's difficult, they are humans too," Erdogan told a conference in Ankara.