Air France is the latest major carrier to ban overflights. Neighbouring Ukraine and Poland are stopping all flights to and from Belarus.
Western countries accuse Belarus of hijacking the Ryanair plane carrying journalist Roman Protasevich on Sunday.
The Greece-Lithuania flight was rerouted over a supposed bomb threat.
Belarus authorities on Monday released video of Mr Protasevich that appears to have been recorded under duress since his arrest.
He faces charges related to his reporting of last August’s disputed election and subsequent crackdown on mass opposition protests, and has said he fears the death penalty after being placed on a terrorism list.
Belarus is the only European country that still executes prisoners.
At a meeting in Brussels on Monday, the leaders of the 27 European Union member states called for the overflight ban, and promised further economic sanctions.
What is happening in the air?
At the Brussels summit, EU leaders told the bloc’s airlines not to fly over Belarus.
They have also asked member states to suspend operating permits for its national carrier Belavia.
Air France said it had “suspended overflights of Belarusian airspace until further notice”. Finnish airline Finnair also announced a ban.
Air France’s Dutch subsidiary KLM, along with German carrier Lufthansa, Scandinavia’s SAS and others, announced similar suspensions on Monday.
Singapore Airlines also said it was rerouting flights to avoid Belarus.
Meanwhile Polish national airline Lot said it had suspended both overflights and flights to and from Minsk, and Ukrainian Foreign Minister Dmytro Kuleba said Ukrainian carriers were banned from flying over or into Belarus.
Belavia said it was suspending flights to the UK and France until 30 October.
Belarus, though not in the EU, borders three EU countries. Many flights to and from Asia as well as within Europe use its airspace.
What prompted the flight bans?
Belarus sent a fighter jet to force Ryanair flight FR4978 – which had departed from the Greek capital, Athens, and was bound for Vilnius in Lithuania – to land, claiming there was a bomb threat. It touched down in the capital Minsk at 13:16 local time (10:16 GMT) on Sunday.
Police then took Mr Protasevich away when the plane’s 126 passengers disembarked. The activist, who witnesses said was “super scared”, was arrested along with his girlfriend Sofia Sapega.
The incident has drawn sharp condemnation from across the world, with countries urging the immediate release of Mr Protasevich and a full investigation.
Ms Sapega’s mother told the BBC that the 23-year-old had been taken to a Minsk jail, adding that the last word she managed to write on her WhatsApp messaging account was ‘Mummy’. The accusations against her are unclear.
“I don’t know what they can charge her with. For going on holiday with Roman Protasevich? It’s his life. What he does is exclusively his choice,” she said.
Belarus said the flight had been diverted because of a bomb threat from the Palestinian militant group Hamas.
But Hamas has denied any involvement. German leader Chancellor Angela Merkel said the Belarusian claim was “completely implausible”.
Dozens of Belarusian officials, including President Alexander Lukashenko, are already under EU sanctions including travel bans and asset freezes, imposed in response to the repression on opponents.
The 66-year-old leader has cracked down on dissenting voices since winning a disputed election last August. Many opposition figures have been arrested, while others fled into exile.
On Tuesday Belarus sentenced seven activists including senior opposition figure Pavel Severinets, to terms of four to seven years for their part in last year’s protests, reports say.
Who is Roman Protasevich, and what has happened to him?
Mr Protasevich is a former editor of Nexta, a media operation with a Telegram channel. He left Belarus in 2019 to live in exile in Lithuania. From there he covered the events of the 2020 presidential election, after which he was charged with terrorism and inciting riots.
Nexta played a key role for the opposition during the vote. It has continued to do so in its aftermath, particularly with the government imposing news blackouts.
Mr Protasevich now works for a different Telegram channel, Belamova.
In the video clip released after his arrest, he said he was in good health and seemingly confessed to crimes he had been charged with by the Belarusian state.
But activists, including the country’s main opposition leader, criticised the video and suggested Mr Protasevich was under pressure to admit wrongdoing.
Mr Protasevich’s father has told the BBC he fears his son may be tortured.
Dmitri Protasevich said on Monday he was “really afraid” of how his son would be treated by the authorities in his home country.
