The reconnaissance plane, which was nearing the Russian border, was identified as R-1 Sentinel. After the UK plane turned away, Russian planes returned to the base.
Last Friday, the Russian Defence Ministry stated that it scrambled a Su-27 fighter jet to escort a US patrol aircraft over the Black Sea.
NATO aircraft have intensified reconnaissance activities near the Russian border over the past month. Moscow has warned that such regular flights by US and NATO aircraft near Russia's border poses the risk of accidental escalation.