Russia sent a MiG-31 jet fighter on Tuesday to intercept a Norwegian patrol plane flying along Russia's border over the Barents Sea, Russian news agencies quoted Russia's Defence Ministry as saying.

The ministry said it had identified the Norwegian plane as an anti-submarine P-3 Orion aircraft and said it had switched off its transponder during the flight, the agencies reported.

Earlier on Tuesday, A Russian Su-27 jet fighter intercepted a U.S. B-52 strategic bomber on Russia's border over the Baltic Sea.