A deadline for Kurdish-led forces in northern Syria to leave areas along the border with Turkey expires later on Tuesday.
Turkey said it wants to establish a safe zone and promised to resume its offensive against the Kurdish fighters if they do not leave.
US President Donald Trump has defended his decision to withdraw some troops from northern Syria, where Ankara has been fighting against Kurdish-backed militias.
Trump said the US has a good relationship with the Kurds, but never agreed to protect them forever.
Al Jazeera's Kimberly Halkett reports from the White House.
