A UN investigation team held Houthis responsible for a December 30 missile attacks on Aden airport that killed at least 28 people.
The report was submitted last week to the UN committee that oversees Yemen-related sanctions, but Russia blocked its wider release, diplomats privy to the matter said.
The Iran-backed Houthis denied responsibility for the attack that took place as members of President Abdrabu Mansur Hadi's government arrived at the airport for talks to form a new Cabinet as part of a Saudi effort to unite its Yemeni allies.
The diplomats did not elaborate on why Russia blocked the release of the findings. The Russian mission to the United Nations did not respond to a request for comment.
At least 28 people died and dozens more were injured in the attack, which the investigators claimed had been launched from two locations that were under the rebels' control at the time – the airport in Taez and a police station in Dhamar, the diplomats said.
No Cabinet minister was killed in the attack, but the casualties included government officials and three Red Cross staff.
The report comes at a sensitive time for US President Joe Biden as his administration and the United Nations press the Houthis to accept a peace initiative that includes a ceasefire.
Saudi Arabia and the Yemeni government have endorsed the initiative but the Houthis say it does not go far enough.
Iran-backed Houthi militias now control most of Yemen's north, and have been fighting forces loyal to Mr Hadi's internationally recognised government and a Saudi-led coalition.
Missile and drone attacks on Saudi Arabia from inside Yemen are on the increase. On Tuesday, Saudi-led coalition forces in Yemen intercepted two explosive-laden drones headed towards the Kingdom.
One drone was intercepted in Yemeni airspace, while the second was brought down before it reached its target at a civilian area in Jizan governorate, Saudi Arabia, said the coalition.
"The [Houthi] militia's hostile attempts to target civilians and civilian objects continue," coalition spokesman Brig Gen Turki Al Malki said.
"We are taking the necessary operational measures to protect civilians," he said.
During Friday's briefing to the sanctions committee, the diplomats quoting the investigators said the attacks were co-ordinated and the missiles that struck the Aden airport were similar to those used previously by the rebels.
When asked if any other party could have been responsible, they said all evidence indicated that no other Yemeni faction had the ability or technology to stage such an attack.
The war in Yemen has claimed thousands of lives and created the world’s worst humanitarian disaster – exacerbated by the Covid-19 pandemic – with the United Nations estimating that 80 per cent of the population needs assistance.