BRUSSELS — The European Union, the US and UK have condemned the diversion of a flight by Belarus on Sunday to arrest a journalist.

European leaders are to discuss the situation at a meeting on Monday, Commission President Ursula von der Leyen said, warning, "the outrageous and illegal behavior of the regime in Belarus will have consequences."

"Those responsible for the Ryanair hijacking must be sanctioned," she added.

Belarus forced Sunday's Ryanair flight FR4978 from Athens to Vilnius in Lithuania to divert before arresting activist Roman Protasevich.

Protasevich, 26, is a founder of a messaging app channel in Belarus that has been a key information conduit for opponents of Belarus’ authoritarian president.

The Belarusian presidential press service said that President Alexander Lukashenko personally ordered a MiG-29 fighter jet to accompany the Ryanair plane to the Minsk airport.

It said a bomb threat was received while the plane was over Belarusian territory; officials later said no explosives were found on board.

The bloc's top diplomat Josep Borrell said in a statement that the arrest constitutes "yet another blatant attempt by Belarusian authorities to silence all opposition voices."

"In carrying out this coercive act, the Belarusian authorities have jeopardized the safety of passengers and crew. An international investigation into this incident must be carried out to ascertain any breach of international aviation rules," he added.

Lithuania said Belarus had effectively held EU citizens hostage by diverting the plane. "The entire EU has been brutally attacked and must respond in the strictest way," its Foreign Ministry said.

It called on the 27-country bloc to consider issuing a joint EU recommendation to avoid entering Belarus airspace and to demand the International Civil Aviation Authority strip the country of its membership.

US Secretary of State Anthony Blinken said Washington "strongly condemn" the Belarusian regime's "brazen and shocking act to divert a commercial flight to arrest a journalist."

"We demand an international investigation and are coordinating with our partners on next steps," he wrote on Twitter. Both Brussels and Washington have called for Protasevich to be immediately released.

Britain's Foreign Secretary Dominic Raab said London is "coordinating with our allies." "This outlandish action by Lukashenko will have serious implications."

The Belarusian Foreign Ministry insisted on Monday that the country's authorities acted "in full conformity with international rules" and accused Europe of politicizing the incident.

"We are struck by the haste with which some countries and European structures have made openly belligerent statements," spokesman Anatoliy Glaz said.

The Russian Foreign Ministry also criticized the West's response with spokeswoman Maria Zakharova writing on Facebook: "It is shocking that the West calls the incident in Belarusian airspace 'shocking'."

She accused Western countries of hypocrisy, citing "violent abductions, forced landings and illegal arrests."

Last November, the Belarusian security services (KGB) placed Protasevich on the list of "individuals involved in terrorist activities".

He was a co-founder of the Nexta Telegram channel that's played a leading role in the wave of protests in Belarus against the 2020 re-election of President Lukashenko, who has held the position since 1994.

The protest movement following the August 2020 presidential election ruled fraudulent by the opposition and Western countries gathered tens of thousands of people in Minsk and other cities, a huge mobilization for a country of 9.5 million inhabitants.

But the protests gradually faltered in the face of mass arrests and police violence that left at least four people dead, with ongoing judicial harassment and heavy prison sentences imposed on activists and journalists.

The EU has so far slapped sanctions on high-ranking Belarusian officials, including Lukashenko, for the electoral fraud and the violent repression of protesters. These sanctions consist of a travel ban to the EU and an asset freeze for 88 individuals and 7 entities.

Protasevich, who had fled the country for Poland, faces charges that could carry a prison sentence of up to 15 years. Exiled Belarus opposition leader Sviatlana Tsikhanouskaya called on the ICAO to begin an investigation.

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

Meanwhile, Ryanair said in a statement on Sunday that it has "notified the relevant national and European safety and security agencies" after being diverted to Belarus and apologized to all affected passengers "for this regrettable delay, which was outside Ryanair's control."

The carrier did not address the arrest of one of its passengers.

Latvia's carrier, airBaltic, announced on Monday that in response to the forced diversion of the Ryanair flight, it has "decided to avoid entering Belarus airspace until the situation becomes clearer or a decision of issued by the authorities."

It already re-routed two of its flights on Sunday — from Riga to Odessa in Ukraine and from Riga to Tbilisi in Georgia — to avoid entering Belarus airspace. — Euronews