Turkey is ready "if necessary" to let in Syrian refugees trapped on its border after fleeing heavy fighting, Turkish President Recep Tayyip Erdogan said.
Tens of thousands of Syrians, mostly women and children, remain stuck at the Turkish border after escaping a Russia-backed government offensive in the Syrian city of Aleppo.
"The regime has now blocked a part of Aleppo ... Turkey is under threat," Erdogan told reporters on his plane returning from Senegal on Saturday.