The plane, a Boeing P-8A Poseidon, known for its intelligence gathering capabilities, was spotted by Mil Radar, an enthusiast service monitoring US Air Force and Navy aviation operations around the world, on Sunday.

US Navy P-8A 168432 PS076 departed Sigonella at 0746z — Black Sea mission pic.twitter.com/aC3wFDmPt3 — Mil Radar (@MIL_Radar) 7 января 2018 г.

According to the service, the plane's transponder showed the P-8A departing from the US military base at Sigonella, Sicily and making its way to the Crimean coast, where it made several loops near Chornomorske and Sevastopol, the latter being the home base of the Russian Black Sea Fleet.

The aircraft then proceeded east toward the Russian mainland and off the cities of Novorossiysk and Gelendzhik, from where it turned around and headed back and out to sea.

Also Sunday, media reported that a heavy US drone, the RQ-4A Global Hawk, call sign 12-2050, conducted a separate recon mission, flying over Ukraine, including the war-torn Donbass region, from where it turned and flew for several hours along the Crimean coast.

The US recon flights near Crimea are already the second and third this year. The first flight took place on New Year's Day. On January 5, a US reconnaissance plane made a separate flight near the borders of the Russian exclave of Kaliningrad in the Baltic Sea.

Since the start of the Ukrainian crisis in 2014, the US and NATO have stepped up their military activities in the Black Sea. Last week, the USS Carney guided missile destroyer entered the Black Sea. According to Ukrainian media, the Tomahawk-carrying warship will likely make a stopover at Ukraine's Odessa port, less than 200 km from Crimea.