An airstrike by the Saudi-led coalition that killed at least 51 people, including 40 children, in Yemen last month was "an apparent war crime", according to a leading rights group.

Human Rights Watch (HRW) made the declaration in a new report on the 9 August strike, which hit a bus carrying children in a busy market in Yemen's northern Saada province.

The attack wounded 79 others, including 56 children, prompting UN calls for an inquiry.

In their report released on Sunday, HRW also demanded an immediate halt to countries selling weapons to Saudi Arabia, which is coordinating action against Houthi rebels engaged in Yemen's civil war.

Bill Van Esveld, HRW's senior children's rights researcher, said: "The Saudi-led coalition's attack on a bus full of young boys adds to its already gruesome track record of killing civilians at weddings, funerals, hospitals, and schools in Yemen.


"Countries with knowledge of this record that are supplying more bombs to the Saudis will be complicit in future deadly attacks on civilians."

Crying children treated after bus airstrike

It has previously been claimed the bomb used in the 9 August attack was sold to Saudi Arabia by the US.

Along with Washington, the UK government has repeatedly come under pressure to suspend arms sales to Saudi Arabia throughout the campaign in Yemen, but has defended its arms exports licensing programme as robust.

After speaking to numerous witnesses of the strike on a rebel-held area, the HRW report revealed they had been told there was "no evident military target in the market at the time".

"Under the laws of war, parties must do everything feasible to verify that targets are valid military objectives," the report added.

"Witnesses said there were no armed men in the market or on the bus, and videos taken on the bus before the attack do not show any fighters or weapons.

"HRW could not confirm the absence of a Houthi military target in the vicinity of the attack, but even if it were present, the use of a weapon with wide area effects in a crowded market would have been unlawfully indiscriminate or expected to cause disproportionate civilian loss."

A 13-year-old boy who was on the bus and suffered a leg injury told HRW: "Even if I am able to run and play in the future, I will not find anyone to play with."

Image: At least 51 people were killed in the attack

On Saturday, the Saudi-led coalition admitted "mistakes" had been made over the airstrike and that it had "caused collateral damage", following its investigation into the attack.

Calling for those responsible to be "punished", coalition spokesman Mansour al-Mansour revealed "an order had been given not to target the bus, which was among civilians, but the order arrived late".

Despite claiming the bus had been carrying Houthi leaders, Mr al-Mansour confessed the "the target did not pose an immediate threat and that targeting the bus in a residential area was unjustified at that time".

The UK government expressed "serious concern at the tragic loss of life in Yemen over the last month", during which more than 400 Yemenis have died and many more have suffered "egregious violations of their basic human rights".

A spokesperson said: "We welcome the speed of the investigation into the incident of 9 August, and the coalition's announcement of regret and action to address the recommendations of that investigation.

"We are reviewing the investigation's conclusions."

They added: "The UK urges all parties to the conflict to do everything possible to protect innocent civilians and to demonstrate their commitment to international humanitarian law."