The Saudi-led military coalition against Houthi rebels in Yemen has denied reports of a deliberate attack on a prison that has killed more than 60 people.

The building in Saada province was not designated as a prohibited target, an Alliance spokesman told the Saudi SPA news agency on Saturday.

It is not on the no-attack lists agreed with the Office for the Coordination of Humanitarian Affairs in Yemen (OCHA) and was not reported by the International Committee of the Red Cross (ICRC).

It also does not fall under the Third Geneva Convention for Prisoners of War.

The OCHA and the ICRC will be informed about the facts and details of the mission.

More than 60 people, including African migrants, were reportedly killed in the attack on Friday. The building was said to be a prison in Saada province, which is held by Houthi rebels. UN Secretary-General Antonio Guterres condemned the attack. His spokesman said other airstrikes had also been reported from other parts of Yemen, killing children.

A proxy war has been raging in Yemen for years between the regional powers of Sunni-dominated Saudi Arabia and Shiite-dominated Iran. The Saudi-led alliance this week intensified airstrikes on alleged Houthi military areas following a previously unprecedented Houthi attack on coalition member United Arab Emirates. Guterres demanded that this escalation must stop. The United States stands with Saudi Arabia. US Secretary of State Antony Blinken said on Friday that the escalation of the conflict was viewed with great concern.

Tens of thousands of people have been killed and millions more displaced in the conflict.

It dates back to 2014, when the Houthis ousted Yemeni President Abd-Rabbu Mansur Hadi, who they accused of corruption and mismanagement.