Ukraine authorities have banned Russian passenger planes from flying to Donetsk and Kharkiv, reports said.
An unidentified employee said Friday Russian airlines had received an order from Ukraine's aviation head banning Russian airlines from entering the airspace around the two cities in eastern Ukraine, Interfax reported.
The employee also said the affected airlines were planning on redirecting flights to other destinations in Ukraine.
The order was made public hours after two helicopters belonging to Ukrainian government forces were shot down over the pro-Russian stronghold of Slovyansk, killing two pilots.
Russian airline Aeroflot subsequently canceled two flights destined for Kharkiv and told passengers they would be able to rebook their flights, free of charge, a statement on the airline's website said.
Transaero Airlines also announced in a statement it was canceling flights to Donetsk.