Alexander Lukashenko told parliament common sense had been abandoned and “many red lines” crossed as Western countries imposed sanctions on Belarus.

He was defending the move to forcibly divert a Ryanair plane, which was flying from Greece to Lithuania, to land in Belarus on Sunday.

A Belarusian journalist who is a critic of Mr Lukashenko was arrested.

Roman Protasevich, 26, was placed on a terrorism list last year and says he fears the death penalty. Belarus is the only country in Europe and the former Soviet Union that still passes and carries out death sentences.

His Russian girlfriend, Sofia Sapega, was also detained. They both now face criminal charges.

Mr Lukashenko’s comments were the first he has made in public about the incident, which has drawn Western outrage.

European leaders have accused Belarus of hijacking the plane, but the president has insisted he acted lawfully when he ordered its diversion.

Belarus claims the flight had been diverted because of a bomb threat from Hamas, but the Palestinian militant group denied any involvement. Mr Lukashenko also said the threat had originated in Switzerland, but the Swiss authorities said they knew nothing of it.

Mr Lukashenko insisted the bomb threat was real, and that the diversion of the Ryanair flight had taken place near a nuclear power plant.

“I had to protect people, I was thinking about the country’s security,” he said, adding that reports that a fighter jet was sent to force the plane to land was an “absolute lie”.

Mr Lukashenko, who has ruled the former Soviet nation for 27 years, accused the international community of interfering in the running of his country.

“This is not information warfare anymore, this is modern hybrid warfare,” he told parliament in the capital Minsk. “We must do everything to prevent it becoming a real war.”

Mr Lukashenko vowed to respond harshly to any sanctions placed on Belarus, and said Western governments were using his country as a “testing site” to gain access to Russia, a close ally.

“The search for new vulnerabilities is under way. And it is directed not only against us . We are training range, a testing site for them ahead of the march to the East,” the president said.

Russia has supported its neighbour.

“The Kremlin sees no reason not to trust statements from the leadership of Belarus,” Dmitry Peskov, the Russian president’s spokesman, told reporters.

EU leaders have already ramped up sanctions against Belarus, and all 27 EU nations, as well as the UK, have banned its airlines from their skies.

A number of airlines have suspended flights over Belarus, including:

The move has a direct impact on Belarus’ revenue, as airlines pay to use a country’s airspace, amounting in millions of dollars per year.

Meanwhile Belarus has accused French authorities of committing an act of “air piracy” after a Belarusian plane flying from Minsk to Barcelona was denied passage through French airspace and turned back.

France has joined Estonia, Ireland, Norway, Britain and the US in signing a joint UN Security Council statement, condemning the “blatant attack on international civilian aviation safety and European security”.

“We fully condemn this as yet another blatant attempt by the Belarusian authorities to silence all opposition voices,” the joint statement said.

The nations are calling on an urgent investigation by the International Civil Aviation Organization (ICAO).

However, it would have to get approval by the UN Security Council and Russia, Belarus’ strongest ally, is a permanent member with veto power.

The US has updated its Belarus travel advisory to “level four, do not travel” due to “the arbitrary enforcement of laws and risk of detention”.

Where is Belarus? It has its ally Russia to the east and Ukraine to the south. To the north and west lie EU and Nato members Latvia, Lithuania and Poland.

Why does it matter? Like Ukraine, this nation of 9.5 million is caught in rivalry between the West and Russia. President Lukashenko has been nicknamed “Europe’s last dictator” – he has been in power for 27 years.

What’s going on there? There is a huge opposition movement demanding new, democratic leadership and economic reform. The opposition movement and Western governments say Mr Lukashenko rigged the 9 August election. Officially he won by a landslide. A huge police crackdown has curbed street protests and sent opposition leaders to prison or into exile.