A prominent opponent of Belarus’s authoritarian president has been arrested after the airliner on which he was travelling was diverted to the country following a bomb threat, in what the opposition called a hijacking operation by the government.

The presidential press service said President Alexander Lukashenko personally ordered that a MiG-29 fighter jet accompany the Ryanair plane — carrying opposition figure Raman Pratasevich and travelling from Athens, Greece, to Vilnius, Lithuania — to the airport in the capital Minsk.

Deputy air force commander Andrei Gurtsevich said the plane’s crew made the decision to land in Minsk, but Ryanair said in a statement that Belarusian air traffic control instructed the plane to divert to the capital.

Lithuanian President Gitanas Nauseda also claimed the plane was forced to land in Minsk and said Mr Lukashenko’s “regime is behind this”.

The Belarusian Interior Ministry said Mr Pratasevich was arrested at the airport. He is a co-founder of the Telegram messaging app’s Nexta channel, which Belarus last year declared as extremist after it was used to help organise major protests against Mr Lukashenko.

Mr Pratasevich, who had fled the country for Poland, faces charges that could carry a prison sentence of up to 15 years.

The presidential press service said the bomb threat was received while the plane was over Belarusian territory. Officials later said no explosives were found on board.

Passengers were taken off the plane in Minsk. After it arrived in Vilnius, defence minister Arvydas Anusauskas said Mr Pratasevich’s girlfriend and four other people did not reboard, adding: “We will find out who are the other four that did not travel with the rest. Lithuania has launched an investigation to find out what really happened on that plane.”

Exiled opposition leader Sviatlana Tsikhanouskaya called on the International Civil Aviation Organisation (ICAO) to investigate.

“It is absolutely obvious that this is an operation by the special services to hijack an aircraft in order to detain activist and blogger Raman Pratasevich,” she said in a statement. “Not a single person who flies over Belarus can be sure of his safety.”

The ICAO said it was “strongly concerned by the apparent forced landing”.

Belarusian authorities said there were 123 passengers on the plane, which resumed its trip to Vilnius later on Sunday, but Lithuanian foreign minister Gabrielius Landsbergis said there were 171.

Western countries also expressed alarm.

European Commission president Ursula von der Leyen tweeted: “It is utterly unacceptable to force @Ryanair flight from Athens to Vilnius to land in Minsk.”

German foreign minister Heiko Maas said: “Such an act cannot be left without definite consequences from the side of the European Union,” and called for Mr Pratasevich to be released.

Months of protests started after last August’s presidential election that official results say gave Mr Lukashenko a sixth term in office.

Police cracked down on the protests, detaining around 30,000 people and beating many of them.

Although protests died down during the winter, Belarus has continued to take action against the opposition and independent news media. Last week, 11 staff members of the TUT.by news website were detained by police.