Since mid-December, Russian-backed regime forces have pressed on with an assault against jihadists in southern Idlib, despite an August ceasefire deal and calls for de-escalation from Turkey, France and the UN.
The Turkish President expressed his concern over a new wave of displacement from Syria as a result of the aggravation of the situation in Idlib, saying: "More than 80,000 Syrian refugees from Idlib have started to migrate towards the Syrian-Turkish borders, and this situation can not be borne by Turkey alone". "Don't do it! Turkey is working hard to stop this carnage", Trump tweeted on Thursday.
The Syrian army said on Monday it had fought fierce battles in southeastern Idlib and seized several villages after killing large numbers of what it called terrorists.
It has pledged to continue its push until it recaptures all of Idlib, calling on civilians to exit areas under jihadist control.
The region is controlled by the rebel group Hayat Tahrir al-Sham and is home to three million people, including many displaced by the country's civil war.
Syrian Bashar al-Assad regime, backed by Russian Federation and Iran, has reportedly promised to take back the rebel-controlled area and broke a ceasefire that was announced in August.
Almost 130,000 civilians have been displaced in Syria's northwestern province of Idlib, the World Health Organization said on December 26.
Few in the German government want to see a repeat of that year's migrant crisis, when Germany had to open its doors to over a million people, most seeking refuge from the Syrian conflict.
Despite a ceasefire announced in August, the bombardment has continued, killing hundreds of civilians and fighters.
Meanwhile, Russian state media on Thursday posted video of Russian troops occupying Tal Samin, a town that was home to a former USA military outpost before Trump chose to withdraw most American troops from northern Syria in October to clear the way for a Turkish invasion.
The move raised fears that vital UN-funded assistance could stop entering opposition-held parts of Syria from January unless an alternative agreement is reached.
The war in Syria has killed more than 370,000 people and displaced millions since it began with anti-government demonstrations brutally crushed by security forces.