EXPLAINER: What was behind a jet's diversion to Belarus?

The diversion of a Ryanair flight to Lithuania by Belarus, leading to the arrest of an opposition journalist who was a passenger, has sparked international outrage and calls for tough sanctions against the former Soviet nation.

Here is a look at what happened in the sky over Belarus and its aftermath.

WHAT HAPPENED ON THE FLIGHT?

Ryanair Flight FR4978, traveling Sunday from Athens to the Lithuanian capital of Vilnius, was in Belarus airspace about 10 kilometers (6 miles) from the Lithuanian border when it changed direction and turned toward the Belarusian capital of Minsk.

Ryanair said Belarusian flight controllers told the pilots that there was a bomb threat against the jetliner and ordered them to land in Minsk. The Belarusian military scrambled a MiG-29 fighter jet in an apparent attempt to encourage the crew to comply with the orders of flight controllers.

Once the plane landed, Belarusian security agents arrested Raman Pratasevich, who ran a popular messaging app that helped organize mass demonstrations against President Alexander Lukashenko, Belarus' authoritarian leader. They also removed from the plane Pratasevich's Russian girlfriend, Sofia Sapega, who studies at a Vilnius university.

Agents with dogs then checked the plane and the passenger luggage, and let the flight continue to Vilnius hours later.

Ryanair's CEO Michael O'Leary described the move as 'œa case of state-sponsored hijacking '¦ state-sponsored piracy.'ť

WHY DID BELARUS DO IT?

To arrest Pratasevich, a 26-year-old activist and journalist who left Belarus in 2019 and faced charges there of inciting riots. He was a blogger and co-founder and editor of Nexta, a popular channel on the Telegram messaging app that was a key factor in organizing protests in Belarus after a presidential election in August 2020.

Lukashenko, who has run the nation of 9.3 million with an iron fist for over a quarter century, was declared the winner by landslide, but the opposition and some election workers say the vote was rigged. Months of protests followed, representing the strongest challenge to Lukashenko's rule since he took over in 1994 following the demise of the Soviet Union.

The Belarusian authorities have unleashed a brutal crackdown on demonstrations. More than 34,000 people have been arrested since August, including opposition activists, and thousands have been beaten and abused by police to try to stem the protests.

Pratasevich was charged in absentia with inciting mass riots, and he faces 15 years in prison if convicted. But the Belarusian state security agency, which still goes by its Soviet-era name KGB, also has put him on a list of people suspected of involvement in terrorism, a sign he could face more serious charges. Terrorism is punishable by death in Belarus, the only country in Europe that still has capital punishment.

A brief video clip of him in custody was shown on Belarusian state television Monday night. He sat at a table with his hands folded in front of him and spoke rapidly, saying he was in satisfactory health, and that his treatment was 'œmaximally correct and according to law.'ť He added that he was giving evidence to investigators about organizing mass disturbances.

WHAT'S THE INTERNATIONAL REACTION?

In unusually swift action, the European Union agreed to impose sanctions against Belarus, banning the country's airlines from using the airspace and airports of the 27-nation bloc.

The EU leaders also urged all EU-based carriers to avoid flying over Belarus, decided to impose sanctions on officials linked to Sunday's flight diversion, and urged the International Civil Aviation Organization to start an investigation.

They also urged Belarus to release Pratasevich and his Russian girlfriend, Sofia Sapega, who was taken off the plane with him.

EU Commission President Ursula von der Leyen said it amounted to a 'œhijacking,'ť and Lithuanian President Gitanas Nauseda called it a 'œstate-sponsored terror act.'ť

The bloc summoned Belarus' ambassador 'œto condemn the inadmissible step of the Belarusian authorities'ť and said the arrest was yet again 'œanother blatant attempt to silence all opposition voices in the country.'ť

U.S. National Security adviser Jake Sullivan raised the issue in his call with the secretary of the Russian Security Council, said White House press secretary Jen Psaki. She added the U.S. was in touch with NATO, the EU, the Organization for Security and Cooperation in Europe, among others about next steps.

Briitain barred Belarus' national airline Belavia from operating in the U.K. and instructed British carriers to avoid Belarusian airspace. Latvian airline airBaltic said it would avoid Belarusian airspace, and Lithuania's government instructed all incoming and outgoing flights to avoid Belarus starting Tuesday, without waiting for the EU decision.

Ukraine President Volodymyr Zelenskyy ordered officials to move to cut the air link with Belarus and ban Ukrainian flights via the neighbor's airspace.

U.N. Secretary-General Antonio Guterres calls for Pratasevich's release and supports calls for 'œa full, transparent and independent investigation into this disturbing incident," U.N. spokesman Stephane Dujarric said.

Belarus can rely on its main sponsor and ally, Russia, which has provided political support and financial assistance to Lukashenko's government amid the protests.