A security personnel and people react during an attack on Aden airport moments after a plane landed carrying a newly formed cabinet for government-held parts of Yemen, in Aden, Yemen December 30, 2020

An investigation by a UN team of experts found Yemen’s Houthis were responsible for a Dec. 30 attack on Aden airport that killed at least 22 people as members of the country’s internationally recognized government arrived, two diplomats familiar with the matter said on Monday.

The experts presented their report to the UN committee that oversees Yemen-related sanctions during closed consultations on Friday, but Russia blocked its wider release, the diplomats said. They asked for anonymity because of the sensitivity of the matter.

The Iran-aligned Houthis denied responsibility for the attack when it took place.

The diplomats did not elaborate on why Russia blocked the release of the findings. The Russian mission to the United Nations did not respond immediately to a request for comment.

The report comes at a sensitive time for new 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.

The Houthi movement, which controls most of Yemen’s north, has been fighting forces loyal to President Abd-Rabbu Mansour Hadi’s internationally recognized government and a Saudi-led coalition in what is widely seen as a proxy war between Tehran and Riyadh.

The UN expert panel determined that the Houthis launched missiles at Aden airport from two locations that were under the movement’s control at the time, the airport in Taiz and a police station in Dhamar, the diplomats said.

The experts found that the missiles were the same kind as those used previously by the Houthis, they said.

The missiles landed as members of Hadi’s government arrived at the airport to join separatists who control the southern port city in a new cabinet as part of a Saudi effort to end feuding between its Yemeni allies.

At least 22 people died and dozens more were injured in the attack.

No Cabinet minister was killed, but the dead included government officials and three International Committee of the Red Cross staff members.

During Friday’s briefing to the sanctions committee, the diplomats said, the experts said the missile launches from the two Houthi-controlled locations were coordinated.

When asked if any other party could have been responsible, they replied that all evidence indicated that no other Yemeni faction had the ability or the technology to stage such an attack, the diplomats said.

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 percent of the population needs assistance.