A Russian fighter jet has safely intercepted a small group of US warplanes over the Baltic Sea during an annual set of military drills, the US Department of Defense said in a tweet.

According to Pentagon officials, the Russian Su-27 fighter intercepted a Boeing KC-135 Stratotanker military refueling aircraft accompanied by two B-1 bombers and one B-52 during the BALTOPS (Baltic Operations) annual training exercise, which started on Saturday.

#Photobomb! A #Russian Su-27 Flanker got into our shot 📸 during a #BALTOPS sortie over the #BalticSea today. The intercept was deemed safe. pic.twitter.com/SMwGfE2QYr — U.S. Dept of Defense (@DeptofDefense) June 9, 2017

Pictures released by the US Department of Defense show the jet flying alongside the American warplanes. Officials said the maneuver was carried out safely.

Another pic I took—A Russian Su-27 fighter merges to intercept 2 @usairforce B1 bombers over the Baltic Sea on June 9 pic.twitter.com/U9AdcvVwzG — Nolan Peterson (@nolanwpeterson) June 9, 2017

A picture I took of a Russian "flanker" fighter on the tail of a @usairforce B-52 bomber over the Baltic Sea today—I was onboard a KC-135 pic.twitter.com/pGbawrCM30 — Nolan Peterson (@nolanwpeterson) June 9, 2017

This was not the only encounter between Russian and NATO air forces to have taken place recently. On June 6, the Russian Ministry of Defense reported intercepting another B-52 bomber over the Baltic Sea, where it was escorted by an Su-27 fighter away from Russian territory. NATO officials have said that Russian pilots generally conduct such maneuvers “safely and professionally.”

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The BALTOPS exercises will go on until 16 June and will involve 5,600 troops from air, sea and ground forces across 12 NATO countries (Belgium, Denmark, Estonia, France, Germany, Latvia, Lithuania, the Netherlands, Norway, Poland, the US and the UK) as well as Finland and Sweden.