The top U.S. military commander in the Middle East made a secret trip to northern Syria on February 24 to meet with allied Syrian forces fighting the Islamic State (IS) group.
General Joseph Votel met with leaders of the Syrian Democratic Forces in the first such trip since President Donald Trump took office.
An alliance spokeman said the visit was "positive"and Votel confirmed U.S. support for the Kurdish-led coalition, which has been the most effective U.S. ally battling IS in Syria.
The alliance has seized swathes of territory from IS across northern Syria, relying on advice and air support from U.S. special operations forces.
The Pentagon has been reviewing its strategy in Syria under orders from Trump to expedite the defeat of IS. Votel said more U.S. troops might be needed to speed the effort, although he said the United States would continue to rely on Syrian ground forces.
"I am very concerned about maintaining momentum," Votel said. "It could be that we take on a larger burden ourselves."
The Syrian forces may not have all the "mobility" and "firepower" needed, he said, "so we have to be prepared to fill in some of those gaps."
Based on reporting by AFP and Reuters