Czech Republic, Poland, Bulgaria close airspace to Russia amid Ukraine conflict

As the Ukraine-Russia crisis intensifies, more countries close airspace to Russia. After the UK, now Czech Republic, Poland and Bulgaria* have closed airspace to Russia.
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*Bulgaria will ban flights to the country operated by Russian airlines and will close its airspace for all Russian aircraft from Saturday, the transport ministry said late on Friday.
The ministry said the move was a result of the escalation of the military conflict and as a sign of solidarity with Ukraine.

Bulgaria closes its airspace for Russian carriers:
(https://www.kaos.gr/2022/02/bulgaria-closes-its-airspace-for.html)
Moscow Bans UK Aircraft From Using Russian Airspace in Retaliation for Aeroflot Sanctions:
(https://www.elethos.gr/2022/02/moscow-bans-uk-aircraft-from-using.html)