The arrest of opposition activist and journalist Roman Protasevich by Belarus police has been met with criticism by UK Foreign Secretary Dominic Raab who said it would have "serious implications".
The journalist's flight was forced to land in Minsk after it was diverted to the country by authorities.
But who is Mr Protasevich and why has he been arrested? Here's what we know:
Who is Roman Protasevich?
26-year-old Protasevich is an opposition activist and journalist who has participated in protests against Belarus President Alexander Lukashenko's government for several years.
He co-administered a social media network against Lukashencko until 2012 when it was hacked by authorities and went on to work for other media organisations in the former Soviet state.
In 2019, after the arrest of his friend Vladimir Chudentsov, Protasevich moved to Poland where he claimed political asylum the following year. He also brought his parents to Poland.
He had claimed his mobile phone had been tapped and he was being followed.
He later relocated to Vilnius, the capital of Lithuania, where opposition leader Sviatlana Tsikhanouskaya is also based.
He co-founded the online news service called Nexta, based in Poland, which Belarus last year declared as extremist after it was used to help organise major protests against Mr Lukashenko.
It used the Telegram messenger app to broadcast at a time when it was hard for foreign media to report first-hand from the country.
Protasevich is currently editor-in-chief of a Belarusian political outlet hosted on the Telegram messaging app called "Belarus of the Brain" which has around a quarter of a million subscribers.
How was he arrested?
Protasevich was arrested by Belarus police on Sunday when a Ryanair flight from Athens to Lithuania was diverted to Minsk.
The Belarus government said President Lukashenko personally ordered that a MiG-29 fighter jet accompany the plane to an airport in Minsk following a bomb threat.
Officials later said that no explosives were found on board.
According to reports, Mr Protasevich had his head in his hands and was shaking when he realised the flight was heading for Minsk.
Passenger Marius Rutkauskas said: "I saw this Belarusian guy with girlfriend sitting right behind us. He freaked out when the pilot said the plane is diverted to Minsk. He said there’s death penalty awaiting him there.
"We sat for an hour after the landing. Then they started releasing passengers and took those two. We did not see them again."
According to Lithuania's Delfi news outlet, another passenger said Protasevich told onlookers: "I'll get the death penalty here" as he was led away.
What has he been arrested for?
Protasevich faces charges that could carry a prison sentence of up to 15 years.
In November, he published a copy of an official Belarusian list of terrorists on Twitter on which he was named.
The listing said he was accused of organising mass riots while working at Nexta.
He also stands accused of disrupting social order and of inciting social hatred.
He regards the allegations as unjustified political repression.
How have international leaders reacted?
Belarus has been condemned for Protasevich's arrest and has been accused of "state terror" with some European leaders accusing the state as "hijacking" the flight.
The incident comes as the EU is set to discuss toughening its existing sanctions against Belarus, imposed over President Lukashenko’s crackdown on opposition protesters, at a preplanned summit on Monday.
Britain's Foreign Secretary Dominic Raab said the UK is "alarmed" by the actions of the Belarus government.
He said: "This outlandish action by Lukashenko will have serious implications."
Ursula von der Leyen, president of the European Commission, said “the outrageous and illegal behaviour of the regime in Belarus will have consequences”.
She added: "Those responsible for the Ryanair hijacking must be sanctioned."
The US said the diversion of the flight was "brazen and shocking" adding: "The United States stands with the people of Belarus."
Meanwhile, the United Nation’s civil aviation agency said the forced landing of the flight could have contravened the Chicago Convention, which protects the sovereignty of a nation's airspace.
NATO Secretary-General Jens Stoltenberg described it as a "serious and dangerous incident which requires international investigation."
He said NATO is closely monitoring the incident and that Belarus should ensure the "safe return of crew and all passengers."