The United States has completed its military pullback in northeastern Syria, settling into a more stable posture of about 600 troops in the rest of the country after repositioning and reducing forces, Defense Secretary Mark Esper said.

Esper's remarks in an interview with Reuters could signal the end of a period of turbulence and uncertainty surrounding the U.S. military presence in Syria after President Donald Trump's initial withdrawal order in October.

Since then, troop levels in Syria have fallen about 40 percent from around 1,000.