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.
BBC report that Mr Protasevich was put on the Belarus terrorist list last year, and faces serious charges.
