An image of the interceptation at 35.000 ft (image by ItAF)

Yesterday morning, around 9 AM (local time) two Italian Air Force Eurofighter Typhoon (belonging to 36th Wing) were scrambled from Gioia del Colle AB (Apulia, southern Italy) to intercept over the skies of Montenegro a TUI Fly Boeing 737-8K5 (D-ATYI ) in flight from Frankfurt to Hurgada (Egypt), which had lost radio contact with air traffic control (ATC).
Here the track of the flight by flightradar24.com:
https://www.flightradar24.com/data/flights/x36102#2017fda6

The Tui 737 entering into Montenegro airspace
(Original image from FR24, elaboration by ItaMilRadar)

The scramble order was issued by Combined Air Operations Center (CAOC) –Torrejon (Spain), the NATO headquarters in charge of surveillance in that area, while the Italian Air Force Air Defence and Surveillance System’s Operations Room provided control over the operation.

From June 2018 Italian and Hellenic Air Force protect Montenegrin airspace participating in NATO air policing mission (Italian and Greek fighter aircraft continues to be based in their home countries, taking to the skies as necessary).

An Italian Eurofighter flies next to a Montenegrin Learjet 45 during a simulated interception exercise. A year on from Montenegro joining the Alliance, NATO has started air policing over the country which does not have its own fighter jets.
(source NATO)