The move has sparked international condemnation with Foreign Secretary Dominic Raab saying he was “alarmed” by the actions of the Belarus government of President Alexander Lukashenko, who is a close ally of Russian President Vladimir Putin.
“We are co-ordinating with our allies. This outlandish action by Lukashenko will have serious implications,” he tweeted.
Germany calling for an immediate explanation and Poland’s prime minister describing it as a “reprehensible act of state terrorism”.
EU member Lithuania has urged the European Union and NATO to respond.
The aircraft, flying from Athens to Vilnius, had almost reached Lithuania when it changed direction and was escorted to Minsk, the Belarusian capital, after reports that it had explosives on board.
Belarusian law enforcers took activist Roman Protasevich, 26 from the plane and detained him.
He was placed on a wanted list after street protests last year following a presidential election in which Lukashenko was declared the winner but opponents complained of electoral fraud.
Lukashenko personally ordered a warplane to escort the Boeing to Minsk, BelTA reported. No explosives were found, it said.
Lithuania and traditional Russian ally Belarus are neighbours and former members of the Soviet Union. Lithuania is now a member of the European Union, Belarus is not.
Lithuanian President Gitanas Nauseda called for an international response.
“I call on NATO and EU allies to immediately react to the threat posed to international civil aviation by the Belarus regime. The international community must take immediate steps that this does not repeat,” Nauseda said.
Lithuanian presidential adviser Asta Skaisgiryte said the operation to force-land the plane carrying around 170 people from 12 countries seemed to be pre-planned.
She said Belarus intelligence services knew who was onboard the plane, which was forced to land with the help of MIG-29 fighter jet. Protasevich had lived in Vilnius since November, she said.
A Lithuanian airport authority spokeswoman told Reuters the plane, scheduled to land in Vilnius earlier on Sunday, was now expected to land later in the day.
Ryanair said the plane’s crew were notified by Belarus of a potential security threat on board and were instructed to divert to the nearest airport, Minsk.
The plane landed safely, passengers were offloaded and security checks were made by local authorities, it said.
The delay was regrettable and outside its control, it added.
The Belarus department for organised crime control also reported that Protasevich had been detained but then deleted the statement from its Telegram channel.
In power since 1994, Lukashenko launched a violent crackdown on the 2020 street protests. Around 35,000 people have been detained since August, human rights groups say. Dozens have received jail terms. Authorities say that more than 1,000 criminal cases have been launched.
Protasevich is one of the founders of the opposition news service NEXT, a Telegram channel that has become one of the main sources of news about demonstrations in Belarus. It is hostile to Lukashenko and helps to coordinate protests.
Belarusian opposition politician Svetlana Tsikhanouskaya, Lukashenko’s main rival at the last election, said Belarus authorities “placed at risk safety of passengers on board and all of the civil aviation for the sake of punishment of the man who was an editor of Belarus’s largest independent Telegram channel”.