Minsk has been accused of playing “Russian roulette” after a Ryanair flight was diverted and a prominent critic arrested in Belarus.
A special meeting of the EU Council was held on Monday evening with the 27 members states agreeing to ban Belarusian airlines from EU airspace and airports.
Speaking in the early hours of Tuesday in Brussels, European Council president Charles Michel said the events were “unacceptable, shocking and scandalous”.
“We will not tolerate that they play Russian roulette with the lives of innocent civilians,” he added.
Mr Michel also called for the release of Mr Protasevich – a critic of Belarussian president Alexander Lukashenko – and his Russian girlfriend Sofia Sapega.
It comes after Transport Secretary Grant Shapps instructed the Civil Aviation Authority to request airlines avoid Belarusian air space “to keep passengers safe”.
He also suspended the operating permit for Belavia, the country’s state-owned airline.
Journalist Roman Protasevich was on board a Ryanair flight from Athens to Vilnius when it was forced to change course to head for Minsk after a bomb scare, escorted by a MiG fighter jet.
In a new video posted online, Mr Protasevich said his being treated well and that reports of heart problems are false.
It was not immediately possible to verify whether the words were his own and had not been recorded under duress.
He was arrested and in a video released by Belarusian authorities on Monday evening appeared to admit he was involved in organising mass protests in Minsk last year.
Seated at a table with his hands folded in front of him and speaking quickly, Mr Protasevich said he was in satisfactory health and his treatment in custody was “maximally correct and according to law”.
US president Joe Biden said he had asked his team to develop appropriate options to hold accountable those responsible.
“This outrageous incident and the video Mr Pratasevich appears to have made under duress are shameful assaults on both political dissent and the freedom of the press,” Mr Biden said in a statement.
“The United States joins countries around the world in calling for his release, as well as for the release of the hundreds of political prisoners who are being unjustly detained by the Lukashenka regime.”
Earlier, Foreign Secretary Dominic Raab said it was “very difficult to believe” the seizure of Mr Protasevich from the flight could have taken place “without at least the acquiescence of the authorities in Moscow”.
He said that although the situation was not yet clear, the relationship between Minsk and Moscow suggested Russian leaders may have been aware of the plans in advance.
In the Commons, he said: “It’s very difficult to believe that this kind of action could have been taken without at least the acquiescence of the authorities in Moscow, but, as I say, it’s unclear as yet.”
Speaking to reporters later, he was asked why he believed it could not have taken place without Russia being aware, and Mr Raab replied: “Based on all the circumstances. But we don’t know – it is just the proximity of the relationship between Minsk and Moscow.”
Ryanair boss Michael O’Leary said the incident was a “state-sponsored hijacking” and claimed agents from Russia’s KGB were on board the flight.
“It was clear it appears that the intent of the Russian authorities was to remove a journalist and his travelling companion. We believe there was also some KGB agents offloaded from the aircraft as well,” he said.
In the EU, leaders also decided to sanction individual officials and called on the International Civil Aviation Organisation to start an investigation into what was seen as an unprecedented move, and what some have called state terrorism.
The bloc summoned Belarus’s ambassador “to condemn the inadmissible step of the Belarusian authorities” and said in a statement the arrest was “another blatant attempt to silence all opposition voices in the country”.
It would also consider “further targeted economic sanctions”, a statement said.
Mr Raab said he would also consider further sanctions against President Alexander Lukashenko’s administration – including the suspension of energy pipelines in Belarus – and the country’s ambassador in London had been summoned for a dressing down.
The Foreign Secretary told MPs there were more than 100 passengers on the flight.
He called for the release of Mr Protasevich from the “spurious charges” he faces, adding: “Mr Lukashenko’s regime must be held to account for such reckless and dangerous behaviour.”
He said the UK is working to explore “every potential diplomatic option” and is “actively considering and co-ordinating with our allies on further sanctions on those responsible for this outlandish conduct”.