Updated

The European Aviation Safety Agency is advising planes to avoid the airspace over Crimea because of possible risks posed by two countries seeking to control the sky in the region.

The agency issued a safety bulletin drawing aircraft operators' attention to "the possible existence of serious risks to the safety of international civil flights." It cited an "unsafe situation where more than one ... provider may be controlling flights within the same airspace" starting Thursday and recommended circumnavigating the so-called "Simferopol flight information region," over Crimea.

The EASA says it acted after Russian authorities issued notices announcing their intention to provide air traffic services in the Simferopol region. Russia has annexed Crimea from Ukraine, a move that Western countries say violated international law.

The recommendation isn't mandatory.