The Saudi-led coalition attack on a funeral in Yemen which killed 140 people was carried out based on false information, an investigation has found.
A body set up by the coalition said the attack in the capital Sanaa was launched based on the incorrect assumption that armed Houthi leaders were in the area.
Mourners killed in the attack included some of Yemen's senior political and security officials. An estimated 525 people were wounded.
The Joint Incidents Assessment Team (JIAT) said in a statement: "A party affiliated to the Yemeni Presidency of the General Chief of Staff wrongly passed information that there was a gathering of armed Houthi leaders in a known location in Sanaa, and insisted that the location be targeted immediately."
The JIAT added that the coalition's Air Operations Centre in Yemen also failed to obtain approval for the strike from commanders - a violation of protocol.
Investigators called for a review of the rules of engagement, as well as for compensation for families of the victims.
They also called for "appropriate action" to be taken against those who caused the incident.
The strike prompted the White House to announce an immediate review of Washington's support for the 18-month military offensive against the Iran-backed Houthis.
Coalition sources initially denied any involvement in the funeral attack, but Saudi Arabia later promised to investigate the "regrettable and painful" incident.
Around 10,000 people have been killed in Yemen's civil war since it began in March 2015, according to UN estimates.