Ukraine on Sunday advised airlines to avoid flying over the open waters of the Black Sea from Monday to Saturday due to Russian naval exercises taking place there.
More than 30 Russian ships have started training exercises near the Crimea peninsula as part of wider navy drills, RIA news agency reported on Saturday.
"From tomorrow, airlines are advised not to fly ...over this area, and to plan optimal routes in advance, taking into account the current situation," Ukraine's state air traffic service said.
It said the airspace over the territory of Ukraine remained open.
A senior Ukrainian official said on Sunday that Ukraine sees no point closing its airspace in response to Moscow's troop build-up, as Dutch airline KLM - part of Air France - said it would stop flying to Ukraine and Germany's Lufthansa said it was considering suspending flights.
The United States has said Russia could invade Ukraine at any time. Moscow denies any plan to invade, saying it is maintaining its own security against aggression by NATO allies.
(Reporting by Pavel Polityuk; editing by John Stonestreet)
