Taoiseach Micheál Martin has joined a number of EU leaders in condemning Belarus over an act of "state terrorism" after the Eastern European country forced a Ryanair flight to land in Minsk so that a wanted opposition activist could be arrested. 

Journalist and activist Roman Protasevich, 26, was detained on Sunday after Ryanair flight FR4978 was forced to divert to Minsk airport from its Athens-to-Vilnius route. 

The flight was accompanied by a Belarussian fighter jet and ostensibly landed due to a bomb scare. 

However, six passengers were not on the flight hours later when it took off to complete its journey to Vilnius. Protasevich and his girlfriend were detained and did not complete the journey to Latvia, while people believe that the four other passengers were Belarussian secret service agents. 

The incident has prompted a furious backlash among European leaders.

The EU was already due to meet at a pre-planned summit on Tuesday to discuss imposing tougher economic sanctions against Belarus due to President Alexander Lukashenko's vicious crackdown on opposition protesters. 

Irish Minister for Foreign Affairs Simon Coveney denounced the incident on Twitter, stating that a "strong and united" approach by EU member states was required.

"It is utterly unacceptable. This is an Irish Airline with EU citizens on board, forced to land in Minsk, while traveling between EU cities. A strong and united response from EU needed. EU inaction or indecision will be taken as weakness by Belarus," Coveney wrote. 

It is utterly unacceptable. This is an Irish Airline with EU citizens on board, forced to land in Minsk, while travelling between EU cities. A strong an united response from EU needed.
EU inaction or indecision will be taken as weakness by Belarus. @dfatirl https://t.co/WUwdcsTjSU

— Simon Coveney (@simoncoveney) May 23, 2021

In an interview with RTÉ's Morning Ireland on Monday morning, Coveney described the incident as an example of "state kidnapping" and "aviation piracy". 

"Only one or two people were actually arrested so that certainly would suggest that a number of the other people who left the plane were secret service. We don’t know from what country but clearly linked to the Belarusian regime," Coveney said on Morning Ireland. 

The Foreign Affairs Minister called for an independent and international inquiry into the incident and said that the EU needed to issue a strong response to make it clear that similar incidents in the future will not be tolerated. 

Coveney added that Lukashenko's election victory last August was "clearly not legitimate". 

Taoiseach Micheál Martin additionally tweeted that the forced landing of the Ryanair flight was "absolutely unacceptable". 

"These unprecedented actions have caused widespread concern across the EU – and they must be addressed at [the EU meeting]," Martin said on Twitter. 

The forced landing of a passenger plane in Belarus today to detain a journalist is absolutely unacceptable.

These unprecedented actions have caused widespread concern across the EU – and they must be addressed at tomorrow’s #EUCO

— Micheál Martin (@MichealMartinTD) May 23, 2021

Meanwhile, President of the European Commission Ursula von der Leyen warned that the "outrageous and illegal behavior of the regime in Belarus will have consequences". 

"It is utterly unacceptable to force @Ryanair flight from Athens to Vilnius to land in Minsk. ALL passengers must be able to continue their travel to Vilnius immediately and their safety ensured. Any violation of international air transport rules must bear consequences," von der Leyen tweeted at 4:23 p.m. on Sunday while the flight was still grounded in Minsk. 

It is utterly unacceptable to force @Ryanair flight from Athens to Vilnius to land in Minsk.

ALL passengers must be able to continue their travel to Vilnius immediately and their safety ensured.

Any violation of international air transport rules must bear consequences.

— Ursula von der Leyen (@vonderleyen) May 23, 2021

Poland’s Prime Minister Mateusz Morawiecki described the incident as "state terrorism" while French Foreign Minister Jean-Yves Le Drian echoed Coveney and called for a "strong and united response" from the European Union. 

Lithuanian and Latvian leaders called on international flights not to use Belarussian airspace. 

Greek Prime Minister Kyriakos Mitsotakis described the forced landing as an "unprecedented, shocking act".

The United States also strongly condemned the incident, with Secretary of State Antony Blinken calling for Protasevich’s release.

"This shocking act perpetrated by the Lukashenka regime endangered the lives of more than 120 passengers, including US citizens," Blinken said in a statement while using an alternate spelling of the Belarussian leader's name. 

Meanwhile, Ryanair CEO Michael O'Leary described the incident as "state-sponsored hijacking". 

Belarussians have taken to the streets since last August to demand the resignation of Lukashenko, who has ruled in Belarus for more than two decades. 

Last year, Protasevich and Stepan Putilo, who founded opposition channel Nexta on the Telegram messaging app, were added to a list of "individuals involved in terrorist activity". 

The two activists were accused of stoking mass unrest and faced up to 15 years in prison, causing both to flee to Poland. 

Belarus also ordered the Nexta Telegram channel and its logo as "extremist" and ordered them blocked. 

Nexta Live, which was edited by Protasevich, and its sister channel Nexta, has more than two million subscribers on Telegram and helped to mobilize protesters in the wake of last August's election. 

Activists say that opposition leader Svetlana Tikhanovskaya was the true winner of last year's election. Tikhanovskaya has fled to neighboring Lithuania to avoid persecution. 

The exiled opposition leader said on Telegram that the forced landing of the Ryanair flight was an "obvious" attempt to arrest Protasevich. 

"It is absolutely obvious that this is an operation of secret services to capture the plane in order to detain activist and blogger Roman Protasevich," Tikhanovskaya said on Telegram. 

Meanwhile, passengers who completed the journey to Vilnius told reporters that Protasevich looked visibly nervous when the flight was diverted to Minsk. 

"He just turned to people and said he was facing the death penalty," Lithuanian passenger Monika Simkiene told AFP reporters after landing in Vilnius. 

"He was not screaming, but it was clear that he was very much afraid. It looked like if the window had been open, he would have jumped out of it," said fellow passenger Edvinas Dimsa. 

Nexta said that all passengers were sent for "another security search" when it became clear that there was no bomb on the aircraft. 

President Lukashenko’s press service released a statement on its own Telegram channel confirming that the plate had been diverted to Minsk on the President's orders and that it had been accompanied by a MiG-29 fighter jet.