A Russian Air Force SU-27 Flanker fighter intercepted a US reconnaissance aircraft that was flying neutral waters of the Black Sea. The interception took place on November 29.
The intercepted aircraft, an RC-135V / W Rivet t despite being in neutral airspace was close to the Russian border, so the fighter was engaged for the intercept.

Rivet t Photo/Reproduction Vida Press
According to a statement from the Russian Ministry of Defense, the SU-27 fighter returned to its departure base after the USAF RC-135 had moved away from the Russian border.
The air base where the USAF RC-135 Rivet t is concentrated is at Offutt Air Force Base, Nebraska. However, reconnaissance aircraft can operate in several other locations around the globe,