A Saudi-led coalition attacked a funeral in Yemen after receiving incorrect information that armed Houthi leaders were in the area, an investigative body set-up by the coalition has said.
More than 140 people were killed in the air strike on 8 October.
The Joint Incidents Assessment Team (JIAT) said coalition air operations officials also failed to obtain approval for the strike from commanders, according to the statement which was carried by state news agency SPA.
The JIAT called for a review of rules of engagement and compensation for the families of victims.
The strike had prompted an international outcry and strong criticism even from Saudi Arabia's closest Western allies.
"Because of non-compliance with coalition rules of engagement and procedures, and the issuing of incorrect information, a coalition aircraft wrongly targeted the location, resulting in civilian deaths and injuries," the inquiry team found.
"Appropriate action ... must be taken against those who caused the incident, and ... compensation must be offered to the families of the victims."
The strike was one of the deadliest in the coalition's nearly 19-month-old bombing campaign in support of Yemen's beleaguered government.
More than 6,700 people have been killed in the impoverished Arabian Peninsula country since the coalition first intervened, nearly two-thirds of them civilians, according to the United Nations.
Britain is to present a draft resolution to the UN Security Council next week calling for an immediate ceasefire in Yemen, after an earlier text condemning the funeral bombing was rejected by Russia as not strong enough.
The inquiry team called on coalition commanders to change their procedures to prevent any repetition of the failings that led to the strike.
The air raid, which targeted the funeral of the father of a senior Houthi rebel commander, also wounded at least 525 people, more than 300 of them critically.
The outcry over the number of civilian casualties prompted the coalition to announce an easing of the air blockade it has enforced since March last year to allow the evacuation of the most seriously wounded for treatment abroad.
Human Rights Watch said that the strike was an "apparent war crime".
The coalition initially denied responsibility but after condemnation from Western governments, it promised an investigation of the "regrettable and painful" event.