According to the Russian aviation watchdog Rosaviatsiya, on Saturday, Russia has restricted flights of the Bulgarian, Polish, and Czech airlines in its airspace after they blocked their airspace to flights by Russian carriers beginning at midnight.

According to Rosaviatsiya, the restrictions were implemented at 12:00 GMT on February 26.

The restrictions apply to all flights to and from Russian airports or via Russian airspace. Flights from these countries are only permitted with the approval of Rosaviatsiya or the Russian Foreign Ministry.

Czech Republic, Poland, and Bulgaria closing airspace to Russian flights

The countries blocked their airspace in response to Russia's special military operation in Ukraine.

Their decisions follow the UK'S to ban the Russian flag carrier Aeroflot on Thursday.

On Friday, Moscow responded by prohibiting all UK-linked planes, including transit flights, from entering Russian airspace.

Similarly, Moldova said Thursday it was closing its airspace and redirecting all planes to other airports, while Belarus announced that it was restricting "part" of its airspace.

The UN Civil Aviation Council condemns Russia's "violation" of Ukraine airspace

On Friday, the UN Civil Aviation Organization criticized Russia's military operation in Ukraine as a violation of its airspace.

In a statement after meeting with governing bodies, the International Civil Aviation Organization (ICAO) Council of 36 nations "condemned the violation of the territorial integrity and sovereignty of a United Nations Member State, including its airspace."

The organization claimed the special military operation was a violation of Article 1 of the Chicago convention, which created the ICAO and the laws governing airspace rights, aviation traffic, and security.

The Council asked Russia to "cease its unlawful activities to ensure the safety and security of civil aviation in all affected areas" and to "respect its obligations" under international air law.

Unlike Ukraine, Russia has an elected member on the Montreal-based agency's council.

Although Ukraine does not have an elected member on the Montreal-based agency's council, unlike Russia, a Ukrainian delegate attended the meeting on Friday due to the council citing "grave concerns on the latest developments" in the country. 

The ICAO does not have the authority to issue fines, but it serves as a platform for governments to establish international aviation standards.

According to its website, in the event that a state violates globally agreed-upon standards, the ICAO's job is "to help countries conduct any discussions, condemnations, sanctions... they may wish to pursue, consistent with the Chicago Convention."

Russian President Vladimir Putin said, on Friday, that the Russian army is successfully carrying out its military mission, preserving security and safeguarding the country.

Putin has made an appeal to Ukraine's troops, urging them to seize control and not allow "neo-Nazis and Banderovites" to exploit children, women, and the elderly as human shields.

Earlier, the Russian President told his Chinese counterpart that Russia is ready to hold high-level negotiations with Ukraine.