A US Air Force jet designed to collect intelligence on enemy radar systems was spotted making circles over Russia, following rising tensions with Moscow. 

Flight tracking data showed the RC-135U 'Combat Sent' taking off from England early Tuesday, flying over the Baltic states and looping around Kaliningrad, the Russian exclave between Poland and Lithuania, before returning to the UK. 

The American jet departed from Mildenhall, a Royal Air Force station in Suffolk, at 2:32am ET and touched down at 9:36am.

The mission came a day after German Chancellor Friedrich Merz accused Russia of waging a 'hybrid war' against Germany.

Merz blamed President Vladimir Putin for the incursion of reconnaissance drones that disrupted Munich Airport and left more than 10,000 passengers stranded.

Flights were canceled during German Unity Day, and as Munich prepared for the final weekend of Oktoberfest, which draws over six million visitors annually.

'He is waging an information war against us. He is waging a military war against Ukraine, and this war is directed against all of us,' Merz told broadcaster NTV on Monday. 

The incursion is the latest in a series of suspected drone overflights across EU and NATO airspace. 

The US Air Force describes the spy plane as providing strategic electronic reconnaissance information to the president, the Secretary of War, Department of Defense leaders and theater commanders

'Locating and identifying foreign military land, naval and airborne radar signals, the Combat Sent collects and minutely examines each system, providing strategic analysis for warfighters,' according to the military branch.

All RC-135U Combat Sent aircraft are fitted for aerial refueling, giving them effectively unlimited range. and carry advanced communications and navigation systems.

Those include high-, very-high- and ultra-high-frequency radios, ground-navigation radar, a Doppler unit, and an inertial system that fuses celestial fixes with GPS. 

The planes are easily recognized by their distinctive antenna arrays on the 'chin' and wingtips, large cheek fairings, and extended tail. 

Crew typically includes two pilots, a navigator, two airborne systems engineers, at least 10 electronic warfare officers known as 'Ravens,' and additional technical specialists. 

The aircraft records and analyzes electronic emissions from foreign radar and communications systems, allowing analysts to identify and map adversary capabilities and develop countermeasures. 

While the reason for Tuesday's mission is unknown, FlightRadar24 also spotted the same craft, callsign JAKE37, taking off from the same airport in England and circling Kaliningrad on October 2, the same day when drones appeared in Germany.

Munich Airport, one of Germany's biggest, was forced to cancel flights late on Thursday and Friday, before reopening from 7:00am local time (1am EST) on Saturday of last week.

The disruption, which saw 46 departures from the airport cancelled or delayed, came as the country celebrated German Unity Day on Friday, a national holiday.

Munich was also gearing up for the final weekend of Oktoberfest, which attracts more than six million people to the city a year, according to the official website.

The incursion was the latest in a series of suspicious drone overflights in European Union airspace and NATO member countries.

Airports in Denmark, Norway and Poland have recently suspended flights due to unidentified drones, with Romania and Estonia pointing the finger at Russia.

Moscow has brushed off the allegations, however.

Kremlin spokesman Dmitry Peskov said: 'There are many politicians in Europe who now tend to blame Russia baselessly and indiscriminately for everything. That's how we view these statements [by Merz].

'The whole story about these drones is strange, to say the least, but Russia should not be blamed without evidence.'