Russia is the only country to support Belarus after it intercepted a plane and detained a dissident. Experts have questioned whether Putin was involved.

• Belarus on Sunday diverted a flight and arrested the dissident Roman Protasevich, who was on board.
• Russia on Monday called it an "absolutely reasonable approach."
• The UK foreign secretary said he suspects Russian knowledge. The Kremlin denied involvement.

Russia is the sole country standing by Belarus after it intercepted a commercial flight and detained an outspoken dissident, prompting experts and officials to suspect Moscow's involvement in the plot.

Roman Protasevich, 26, was taken into custody on Sunday after a Ryanair plane carrying him from Greece to Lithuania was forced to land in Belarus after the pilots received a fake security report from local authorities. Ryanair CEO Michael O'Leary said he believed KGB agents were on the diverted flight.

The UK, US, and the EU slammed Belarus' move, calling it a violation of aviation law and human rights.

Meanwhile, Russia has defended Belarus' actions and used it to accuse western nations of hypocrisy.

On Monday, Russian Foreign Minister Sergei Lavrov that Belarus had treated the incident with an "absolutely reasonable approach."

Maria Zakharova, a Russian foreign ministry spokeswoman, also wrote in a Facebook post: "The internet remembers all cases of violent abductions, forced landings and illegal arrests made by 'peace officers and guardians of morality,'" referring to western democracies.

'Belarus would not have hijacked an EU plane without Russian approval'

Even before Russia's show of support to Belarus, experts have suspected its involvement.

Belarus is heavily reliant on Russia financially, with Moscow long working to lure Belarus away from western European alliances.

Belarusian President Alexander Lukashenko has also turned to Russian President Vladimir Putin for support in the past: When anti-government protests swept Belarus last fall, Lukashenko publicly asked Putin for help, and Putin sent support in the form of state-media journalists and surveillance resources, European intelligence sources told Insider at the time.

In a series of tweets Sunday, Timothy Snyder, a history professor at Yale University, said: "Belarus would not have hijacked an EU plane without Russian approval" and that "possibly the hijacking was even a Russian initiative."

In response, Nigel Gould-Davies, the former UK ambassador to Belarus, said he "had no reason to believe" the theory that Russia orchestrated the plot, but added "that doesn't mean to say Russia doesn't approve or didn't assist."

On Monday, Britain's foreign secretary also suspected Russian knowledge in the interception.

"It's very difficult to believe that this kind of action could have been taken without at least the acquiescence of the authorities in Moscow," Dominic Raab said, according to Reuters , caveating that he didn't have "any clear details" on Russian involvement so far.

Timothy Ash, a senior emerging-markets strategist at Bluebay Asset Management, also said Monday that Lukashenko "would not have risked his relationship with the Kremlin by undertaking such a cavalier move unless he had been first given the green light by Putin," CNBC reported.

Russia has denied any involvement in the interception. Kremlin spokesman Dmitry Peskov on Tuesday dismissed the idea that his country knew anything about the Belarus plot, saying that widespread anti-Russian sentiment meant that Russia is accused of everything these days, Reuters reported.