An unnamed Pentagon official told ABC News the report was false because the U.S. is not flying any drone missions over Crimea, the segment of Ukraine that Russian troops are stationed.
Rostec, a Russian state owned media company, reported the U.S. drone was flying at 12,000 feet when a cyber attack forced it to make an emergency landing. The Voice of Russia reported the drone was an MQ-5B Hunter with the "66th U.S. brigade of military intelligence with the main location in Bavaria."
A couple issues with that report besides the denial from the Pentagon.
First, the MQ-5 Hunter is one of the oldest, most basic drones in the U.S. fleet that the Army has since replaced with the RQ-7 Shadow. Even if the Russians mistook the drone for a Shadow, it seems unlikely the U.S. would fly one of their slowest and least powerful drones in the U.S. fleet.
If the U.S. military flew an intelligence and surveillance collection mission over Crimea with a drone, it seems a lot more likely the U.S. would tap the Air Force to fly its stealth drone for such a sensitive mission -- the RQ-170 Sentinel. Tough to mistake the Sentinel for the RQ-5 Hunter.