After the forced landing of a Ryanair passenger plane in Belarus and the subsequent arrest of a government critic, EU Commission President Ursula von der Leyen speaks of a "kidnapping".

"Those responsible for the Ryanair hijacking must be sanctioned," wrote von der Leyen on Twitter on Sunday evening.

She also called for the immediate release of the blogger and journalist Roman Protasewitsch and said that the EU heads of state and government would discuss how to proceed on Monday.

The authorities in Belarus forced Ryanair's Boeing plane to land on its way from Greece to Lithuania on Sunday.

The pilots of the Ryanair plane with 170 passengers on board were forced to turn due to a suspected bomb alarm, and a military jet escorted them to Minsk Airport in Belarus.

Also on board was Roman Protasevich, who lived in exile and was an avowed opponent of Belarusian President Alexander Lukashenko.

He was arrested in Minsk.

The machine later continued its flight with the remaining passengers.

Lithuania calls for "strong transatlantic response"

Lithuania is counting on a common response from the West.

Secretary of State Gabrielius Landsbergis said he had spoken to US Deputy Secretary of State Philip Reeker about the incident.

It had been discussed "that the unprecedented event must find a strong transatlantic reaction".

The Lithuanian public prosecutor opened a criminal investigation into the proceedings on Sunday.

Among other things, it is about the possible hijacking of an aircraft for terrorist purposes and the violation of international treaties, the authorities said.

Lithuania's Prime Minister Ingrida Simonyte said several people who landed by plane in Vilnius, Lithuania on Sunday evening had been asked to testify immediately.

The US condemned the forced stopover and the arrest of the exiled opposition member "in the strongest possible terms".

This "shocking act" by the government of Belarusian ruler Lukashenko endangered the lives of more than 120 passengers, "including US citizens," said US Secretary of State Antony Blinken.

With regard to the arrested opposition activist Protasevich, Blinken said: "We demand his immediate release".

"Initial reports indicating the involvement of the Belarusian security services and the use of Belarusian military aircraft" are "deeply worrying," added Blinken, calling for a full investigation into the events.