Russia has denied entry to two European airlines because they planned to avoid flying over Belarus to get to Moscow.
Air France and Austrian Airlines have both had to cancel services after their flight plans were rejected by Russia.
Some airlines are avoiding Belarusian airspace in protest after the government there forced a Ryanair plane to divert and land in Minsk on Sunday.
A Belarusian dissident journalist and his girlfriend were then arrested.
Russia is a strong ally of Belarus, and has remained steadfast in its support of the former soviet nation and its government.
It is the first move from the Kremlin over the diplomatic conflict between Belarus and Western countries. Russia is yet to comment on whether all flights will be denied entry if they avoid the airspace.
The European Union and UK have banned Belarusian airlines from flying over their territories, and have said more sanctions are to come, including against Belarus’s president of 27 years, Alexander Lukashenko, and other senior officials.
The European airspace ban has forced Belarusian carrier Belavia to cancel 12 of its routes until 30 October, according to Reuters news agency. The routes affected are Amsterdam, Barcelona, Berlin, Brussels, Frankfurt, Hanover, Kaliningrad, Milan, Munich, Rome, Vienna and Warsaw.
A number of European airlines have stopped flying to or over Belarus, a move which directly affects the country’s revenue, because airlines pay to use a country’s airspace, amounting to millions of dollars per year.
In response, Russia rejected the flight plans of the Air France and Austrian Airlines planes, which showed them circumnavigating Belarus.
At least four Air France flights between Paris and Moscow have been cancelled. Some passengers were rebooked on Russian carrier Aeroflot.
Two Austrian Airlines flights have been grounded – one passenger plane travelling from Vienna to Moscow, and a cargo plane travelling from Nanjing in China to Vienna.
Austria’s foreign ministry said Russia’s actions were “absolutely incomprehensible”.
The French ministry of transport told AFP news agency that “the principle of reciprocity… must be respected”.
Tracking website Flightradar24 showed little activity in the skies over Belarus on Thursday, except for Belarusian and Russian airlines.
On Wednesday, the website showed a Minsk to Barcelona flight, operated by the Belarusian airline Belavia, in a long holding pattern at the border with Poland, which has banned Belarusian flights from its airspace. The plane eventually returned to Minsk. The BBC has contacted Belavia for clarification on why it turned back.
Why is this happening?
On Sunday, Ryanair Flight 4978 was travelling from Athens to Vilnius, when it was forcibly diverted to the capital of Belarus, Minsk. A fighter jet was scrambled to tail the plane and ensure it changed course.
Aboard was prominent opposition activist Roman Protasevich, 26, who lives in exile in Lithuania, and his girlfriend Sofia Sapega, 23, an international law student. They were arrested as passengers disembarked the plane.
Mr Protasevich was put on the Belarus terrorist list last year, and faces serious charges.
On Thursday, Mr Protasevich was able to see his lawyer for the first time.
“All is well, he is vigorous, positive and cheerful, there is nothing to worry about,” Inesa Alenskaya was quoted as saying by the Belorusskiye Novosti website, adding she could not give any more information away.
Russia’s foreign ministry says Miss Sapega is accused of breaking Belarusian law in August and September of 2020. But it is unclear what these crimes are.
Videos were released showing the pair confessing to crimes, but it is likely they were speaking under duress.
The forced landing of the plane and their arrest caused international outrage.
“It was a serious attack on the rules governing civil aviation… This action also represents a serious attack on media freedom,” a statement by the G7 nations of Canada, France, Germany, Italy, Japan, the UK and the US said.
The UN’s International Civil Aviation Organization (ICAO) has agreed to investigate the grounding of the passenger plane.
We strongly condemn the forced landing of a Ryanair flight in Minsk and the detention by Belarusian authorities of journalist Raman Pratasevich and Sofia Sapega. We call on @ICAO to urgently investigate this unacceptable incident and for full accountability for those responsible. pic.twitter.com/1oPS9aV5Nw
— U.S. Mission to the UN (@USUN) May 26, 2021
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Belarus: The basics
Where is Belarus? It has its ally Russia to the east and Ukraine to the south. To the north and west lie EU and Nato members Latvia, Lithuania and Poland.
Why does it matter? Like Ukraine, this nation of 9.5 million is caught in rivalry between the West and Russia. President Lukashenko has been nicknamed “Europe’s last dictator” – he has been in power for 27 years.
What’s going on there? There is a huge opposition movement demanding new, democratic leadership and economic reform. The opposition movement and Western governments say Mr Lukashenko rigged the 9 August election. Officially he won by a landslide. A huge police crackdown has curbed street protests and sent opposition leaders to prison or into exile.