A group of U.S. Army Green Berets were deployed to Saudi Arabia’s border with Yemen and they were tasked with finding and destroying ballistic missiles and launch sites in the conflict zone.
By Department of Defense (http://www.dodmedia.osd.mil/) [Public domain], via Wikimedia Commons
The news was first reported by New York Times, who claimed the information was provided American officials and European diplomats.
However, the Times says there is no indication that the special forces entered Yemen.