Aeroflot (SU, Moscow Sheremetyevo) has cancelled all flights to Kharkiv and Donetsk until May 5 after Ukrainian aviation authorities unilaterally banned all Russian airlines from the serving the two eastern cities from May 2 onwards.

Russia's Interfax news agency says Aeroflot has now redeployed the aircraft that would have been used on the flights, to Simferopol in the recently annexed Crimean peninsula.

In a statement, the Russian Federal Air Transport Agency (Rosaviatsia) labelled the ban an "unprecedented violation of international air traffic agreements" which "heavily encroached on the rights of passengers" and which "could lead to a humanitarian blockade of residents in south-eastern Ukrainian regions."

In recent weeks, both Donetsk and Kharkov have been the scene of intense street fighting and civil disturbances between Pro-Russian separatists and Ukrainian security forces.