VILNIUS, LITHUANIA (REUTERS) - A United Nations report into the forced diversion of a Ryanair jetliner last year has found that a bomb threat which drew the plane to Minsk was "deliberately false" and that Belarus withheld crucial information from its fact-finding team.

The UN's International Civil Aviation Organisation (Icao) set up a specialist fact-finding team in May 2021, days after Belarus diverted the Vilnius-bound jet carrying a wanted opponent to Minsk following what it described as a bomb threat.

Dissident Belarus journalist Roman Protasevich and his Russian girlfriend were detained in Minsk following the diversion, which took place shortly before the jet was due to leave Belarus airspace, prompting international uproar.

Protasevich's girlfriend Sofia Sapega has since been charged with inciting social hatred and could face up to 12 years in prison, while he remains under house arrest.

The report, sent to Icao's 193 member states on Monday (Jan 17), said Belarus authorities did not properly contact Ireland-based Ryanair about the alleged bomb threat, despite regulations urging them to do so, and did not help crew talk to their base.

The pilots agreed to divert to Minsk after a Belarus air traffic controller declared "code red", indicating a credible threat to the aircraft necessitating an immediate landing.

It is improbable that Ryanair would have agreed to declare "code red" in the circumstances, said the report, which concluded that the bomb threat was "deliberately false". No person or state has been identified as the source of an apparently illegal hoax, it said.

European Union leaders and human rights groups have accused Belarus of fabricating the bomb threat in order to lure the plane to its territory and enable the arrest of Protasevich.

Belarus has said it acted legally and in accordance with all international norms, and accused the West of trying to use the episode to try to undermine President Alexander Lukashenko.

A Belarus presidential spokesman did not immediately respond to a request for comment on the Icao report.

Citing a pilot witness, the report said a search for the alleged bomb inside the cabin on the ground in Minsk was cursory and took just 18 minutes to complete.

Emergency services were told to stand down before the search was over and before the baggage hold was opened for checks, it said. Despite the supposed threat, disembarking passengers took 30 minutes and the pilot was allowed to remain onboard, it said.

Icao also laid out lapses in co-operation with its mission.

Its team "was not provided with a satisfactory rationale to explain why records had not been preserved" considering that local criminal and other investigations were under way.

Belarus also refused to provide access to the controller of the Ryanair flight or to the call records of officials, nor did it provide footage from well-placed airport cameras.

The investigation was not given a copy of an e-mail containing the bomb threat or e-mail server logs, the report added. It cited data from a Switzerland-registered e-mail provider as showing the e-mail was sent only after the jet had begun its descent towards Minsk.

Belarus told the investigation it received the e-mail 30 minutes earlier but provided only a screenshot as a proof.

Ryanair had no immediate comment on the report.

The report is the first international finding since Belarusian carriers were banned from flying over EU and British territory. The EU and Britain have also urged their airlines to avoid Belarusian air space unless in an emergency.

The EU has imposed travel bans and asset freezes on 86 Belarusian individuals and companies, including transport and defence ministers, in response to the grounding.