Minsk, May 27 (IANS): Belarusian President Alexander Lukashenko has defended a decision to force the landing of a Ryanair passenger plane with a dissident journalist on board.

The forced landing on Sunday has been sharply condemned by members of NATO as well as the UN Security Council, reports dpa news agency.

"I acted lawfully by protecting people, according to all international rules," Lukashenko told Parliament in Minsk on Wednesday.

Authorities used Sunday's landing to have dissident Belarusian journalist Roman Protasevich arrested at the airport in Minsk.

Protasevich is a "terrorist", added Lukashenko, who said the 26-year-old blogger was planning a "bloody uprising" in Belarus.

"There was a terrorist on board the plane," he said, claiming that it was his country's sovereign right to detain its own citizens.

Lukashenko initially said, without elaborating, that Belarus had received information that there was an explosive device on the plane.

Therefore, he said, the plane, which was on its way to Lithuania from Greece, was diverted to Minsk with the assistance of a fighter jet.

"That the plane was forced to land by a MiG-29 fighter jet is an absolute lie," said Lukashenko.

Belarus acted for safety reasons, he said, because the plane flew over the country's nuclear power plant.

The European Union has imposed new sanctions on the power apparatus in Belarus in the wake of the action, including a landing ban for the country's airlines and sanctions on the leadership.

NATO condemned the action on Wednesday.

The body's North Atlantic Council said the "unacceptable act seriously violated the norms governing civil aviation and endangered the lives of the passengers and crew".

Protasevich and his partner, Sofia Sapega, should be released and there should be an "urgent independent investigation", it added..

Many current and former members of the UN Security Council have also condemned the forced landing of a passenger flight.

"It constitutes a new and extremely dangerous phase in the Belarusian authorities' campaign of repression against its own people," said a statement from the UN representation of Estonia, supported by France, Ireland, Belgium, Germany, Norway, Britain and the US.

Together they demanded an investigation into the incident and Protasevich's release.

A joint statement by all 15 members of the Security Council failed, among other reasons due to Russia's opposition.

Belarus threatened to react to the latest sanctions with ones of its own, though Prime Minister Roman Golovchenko said the decision would not be made hastily.

"We suggest soberly thinking again before you go down the slippery slope of an economic war in which there will be no winners," he said, adding that the measures would be painful but leaving open whether they would apply to goods or oil and gas transport to Europe.

More than 100 people were on board the Ryanair flight that was forced to land, including Protasevich and his partner.

Both were arrested and their fate remain uncertain.

Poland has decided to close its airspace for planes operated by Belarusian carriers, government spokesperson Piotr Mueller said on Wednesday.

The website Flightradar showed an aircraft of the Belarusian airline Belavia flying several loops on the route from Minsk to Barcelona before entering Polish airspace and finally turning back towards Minsk.

According to the airline, France had revoked a previously issued overflight permit.

Attempts to take alternative routes had been unsuccessful, the airline said in Minsk.

Prime Minister Ingrida Simonyte of neighbouring Lithuania has expressed concerns, saying: "This is an unpredictable regime from which you can expect anything, and you have to be prepared for anything. "

Lukashenko made other claims about Protasevich's past, including that he had fought on the side of government forces in eastern Ukraine and had "a lot of experience as a mercenary".

Protasevich had reported from Ukraine in 2014, when the war between pro-Russian forces and the central government in Kiev was breaking out.

However, it has never been proved that he engaged in combat.