Ukraine closed its airspace to the Russian air force on 3-5 April after claims that its aircraft had violated air traffic control (ATC) procedures over the Black Sea near Odessa in March.
Gen Alexander Zatynaiko, Ukrainian Chief of Staff, claims that the aircraft were flying with their transponders switched off, failed to respond to ATC radio messages and changed altitude without warning. Odessa Airport was forced to close for 30min.
Ukrainian fighters were scrambled to intercept the Russian aircraft, identified as Tupolev Tu-22R and Antonov An-30 reconaissance aircraft, and Ilyushin Il-76 and Antonov An-24 transports.
Russia denies violating any rules, saying that the aircraft took off from an air base in the Saratov region and entered international airspace through the Russian sector of the Black Sea coastline near Novorossiysk. They then reportedly headed west to monitor the movements of NATO ships visiting Odessa.