The US State Department's anti-ISIL coalition envoy Brett McGurk told CBS News that the 50 US Army Special Forces troops are scheduled to go into Syria "very soon."
"They will be going in very soon," McGurk told CBS, adding that the precise timing is sensitive information.
McGurk also said that Syria has a dire situation with foreign fighters. The US envoy compared the situation to the Soviet-led war in Afghanistan, during which the US sent in advisors, as well as funded and trained Islamist militants to fight Soviet forces and the country's government.
"We've never seen anything like this. 30,000 foreign fighters from a hundred countries around the world, that's almost twice as many as went into Afghanistan in the eighties, " McGurk said.
Syrian President Bashar al-Assad previously voiced many concerns about foreign fighters among rebels, even before ISIL's separation from other terrorist groups fighting the Syrian government, including the al-Qaeda-affiliated al-Nusra Front.
McGurk also said that the talks being held on Syria's future in Vienna are crucial for Syria's future, although he noted that the US remains committed to "transitioning" Assad out of power.