Russian air defence systems detected US reconnaissance planes over neutral waters in the Black Sea, they were then escorted by a Russian Su-30 fighter, the Defence Ministry said in a statement.
The US planes were continuously tracked by Russian radar monitoring equipment at a considerable distance from the Russian state border, the ministry added.
On 17 June, the USS Porter, a US Navy Arleigh Burke-class destroyer, entered the Black Sea, according to information of Russia's National Defence Control Centre (NDCC).
In May, the Russian military said that they spotted US Air Force B-1B strategic bombers over the Black and Baltic Seas, and scrambled fighter jets to intercept them. The Russian fighter jets approached the US bombers and the latter turned away from the Russian border, the Defence Ministry said.
The Su-30SM was developed by Russia's Sukhoi Company for the needs of the Russian Defence Ministry, according to the firm’s website. The aircraft performed its maiden flight in September 2012.
