MOSCOW — International outrage mounted on Monday as new details emerged about a brazen operation by the country’s strongman leader to divert a Ryanair passenger jet and arrest a dissident Belarusian journalist traveling on board.
Secretary of State Antony J. Blinken condemned the forced diversion of a civilian airliner and the arrest of the journalist, saying it was a “shocking act” that “endangered the lives of more than 120 passengers, including U.S. citizens.”
“Initial reports suggesting the involvement of the Belarusian security services and the use of Belarusian military aircraft to escort the plane are deeply concerning and require full investigation,” Mr. Blinken said.
Michael O’Leary, the chief executive of Ryanair, an Irish-based low-cost carrier, called the operation, which was directed by President Aleksandr G. Lukashenko of Belarus, a “state-sponsored hijacking.”
Leaders from the European Union were expected to meet Monday night to discuss possible penalties.
Sofia Sapega, the girlfriend of the arrested journalist, Roman Protasevich, was also detained when the plane landed in Minsk on Sunday after a bogus bomb threat during its flight from Athens to Vilnius, Lithuania, her university in the Lithuanian capital said.
Ms. Sapega, a Russian citizen, was detained at the Minsk airport along with Mr. Protasevich under “groundless and made-up conditions,” the European Humanities University in Vilnius said in a statement demanding her release.
There was no word Monday morning from the Belarusian authorities on their whereabouts.
At least six people who boarded in Athens were not on the plane when it finally arrived in Vilnius, the police commissioner of Lithuania said on Monday.
Mr. O’Leary said some of the passengers may have been agents of the Belarusian intelligence service, which is still known by its Soviet-era initials.
“We believe there were some K.G.B. agents offloaded at the airport as well,” Mr. O’Leary told Irish radio on Monday.
Mr. O’Leary said Ryanair was in the process of debriefing its crew and that the European Union and NATO were “dealing with” the situation.
The Lithuanian government called for Belarusian airspace to be closed to international flights in response to what it called a hijacking “by military force.”
The Lithuanian police said they had opened a criminal investigation, on suspicion of hijacking and kidnapping.
“What I know is that six people did not arrive in Vilnius,” Renatas Pozela, Lithuania’s police commissioner general, said in a telephone interview with The New York Times.
Further details, he said, “are being looked into as part of the criminal investigation.”
The Lithuanian police spoke to the pilots after they landed in Vilnius on Sunday evening, Mr. Pozela said.
Police investigators would be interviewing the passengers this week, he said.
“The pilots were the priority,” Mr. Pozela said. “We wanted to hear their stories. How did they see the situation? What did they do? Were there other planes?”
Mr. Pozela said he was not yet authorized to disclose any findings of the investigation.
The chorus of condemnation and outrage from across the European Union swelled overnight as leaders began discussing possible penalties they could direct at Belarus for its forcing down of a civilian passenger jet.
However, they are somewhat limited in the actions at their disposal, because there are already E.U. sanctions against Aleksandr G. Lukashenko, the brutal and erratic leader of Belarus who has clung to power despite huge protests against his government last year, and dozens of his immediate associates.
In a summit scheduled to take place Monday evening, European leaders are expected to discuss adding aviation-related sanctions.
The options may include designating Belarusian airspace unsafe for E.U. carriers; blocking flights from Belarus from landing in E.U. airports, and sanctions against the national flag carrier, Belavia.
E.U. leaders also called for an investigation into the circumstances of the incident by the International Commercial Aviation Organization.
Prime Minister Kyriakos Mitsotakis of Greece, where the flight originated, said it was critical the European Union take specific action, especially in the context of the bloc’s frequent paralysis over foreign-affairs issues including a recent failure to agree on a statement regarding the Middle East conflict.
“Our inability to reach a consensus on recent events in Israel and Gaza — where as a union we failed to present a unified stance — must not be repeated,” Mr. Mitsotakis told the Financial Times. “The forcible grounding of a commercial passenger aircraft in order to illegally detain a political opponent and journalist is utterly reprehensible and an unacceptable act of aggression that cannot be allowed to stand.”
Ursula von der Leyen, the president of the European Commission, the bloc’s executive arm, also promised action at the leaders’ summit.
“The outrageous and illegal behavior of the regime in Belarus will have consequences,” she said in a tweet Sunday evening, adding that there must be sanctions for those “responsible for the #Ryanair hijacking.”
Aleksandr G. Lukashenko, the strongman ruler of Belarus and the most enduring leader in the former Soviet Union, appeared undeterred by the international outcry that has erupted after his country forced a civilian passenger jet to land and then arrested a dissident journalist who was onboard.
Rather than try to blunt diplomatic fallout on Monday, he signed new laws cracking down further on dissent.
The country placed bans on publishing unauthorized public opinion polls, on the livestreaming of unauthorized protests, and even on posting links to “banned” information.
The Belarusian Foreign Ministry’s spokesman, Anatoly Glaz, insisted that what happened to the jet was in strict accordance with aviation rules and said the country was prepared to host international experts “in order to rule out any insinuations.”
Russia, Mr. Lukashenko’s main ally, stood by him.
Maria Zakharova, the Russian Foreign Ministry’s spokeswoman, compared Sunday’s incident to the forced diversion of a plane carrying Bolivia’s president, Evo Morales, which made an unscheduled landing in Austria when he was flying home from Moscow in 2013 after other European countries refused it permission to refuel or to use their airspace.
“I’m shocked that the West is calling the incident in Belarusian airspace ‘shocking,’” Ms. Zakharova wrote on Facebook.
Dmitri S. Peskov, the Kremlin’s spokesman, also refused to join the chorus of condemnation in the West.
“The international aviation authorities need to evaluate whether or not this followed or did not follow international norms,” he told reporters. “I cannot comment on anything in this situation.”
A day after the dissident journalist Roman Protasevich was detained in a plot that most Hollywood producers would have dismissed as improbably dramatic, there has been no word about where he is, how long he could be held, or what will happen to him.
Mr. Protasevich, an exiled opposition figure, was taken into custody on Sunday after the flight he was on was intercepted while traveling from Athens to Vilnius, Lithuania, by a MiG-29 fighter jet under orders from the strongman president of Belarus, Aleksandr G. Lukashenko, and diverted to Minsk.
Mr. Protasevich is a co-founder and a former editor of the NEXTA channel on the social media platform Telegram, which has become a popular conduit for Mr. Lukashenko’s foes to share information and organize demonstrations.
Mr. Protasevich became a dissident as a teenager, drawing scrutiny from law enforcement. He was expelled from a prestigious school for participating in a protest rally in 2011 and later was expelled from the journalism program at the Belarus State University.
He fled the country in 2019, fearing arrest. But he has continued to roil Mr. Lukashenko’s regime while living in exile in Lithuania, to the extent that he was charged in November last year with inciting public disorder and social hatred.
The government’s main security agency in Belarus, called the K.G.B., had placed Mr. Protasevich’s name on a list of terrorists. If he is convicted of terrorism, he could face the death penalty.
The charges of inciting public disorder and social hatred carry a punishment of more than 12 years in prison.
Sofia Sapega, a 23-year-old Russian citizen and the girlfriend of Mr. Protasevich, was traveling with him on the flight, and she was also detained, according to a statement from the European Humanities University in Lithuania where she is a student. The university said she was detained on “groundless” conditions and pleaded for help in securing her release.
Anna Schaverien contributed reporting.
Shortly after Ryanair Flight 4978 crossed in the airspace of Belarus, an alarming message came crackling over the radio.
The pilots were told of “a potential security threat on board.” A possible bomb.
The plane, headed from Athens in Greece to Vilnius in Lithuania, would have to be diverted to Minsk, the capital of Belarus.
And if there was any doubt about the seriousness of the situation, the pilots only needed to look out of their window, where a MIG-29 fighter had suddenly appeared to escort them.
Aleksandr G. Lukashenko, the ruler of Belarus who is often referred to as “Europe’s last dictator,” personally ordered the fighter jet to intercept the passenger plane — a fact his office proudly noted in a news release.
According to the statement, Mr. Lukashenko gave an “unequivocal order” to “make the plane do a U-turn and land.”
After the plane was forced to land, Roman Protasevich, a dissident journalist, was arrested. His girlfriend, Sofia Sapega, was also on the flight, and she, too, did not board the plane again.
The country’s interior ministry announced Mr. Protasevich’s arrest in a statement that was later deleted from its official Telegram channel.
After about seven hours on the ground in Minsk, the passenger jet, a Boeing 737-800, took off for Vilnius, landing there safely 35 minutes later.
No bomb was found on board, according to law enforcement authorities in Belarus. The Investigative Committee, Belarus’s top investigative agency, said it had opened a criminal case into a false bomb threat.
“Nothing untoward was found,” Ryanair said in statement.