A UN human rights body has called on Saudi Arabia to end airstrikes in Yemen and start ensuring the perpetrators of attacks on children are brought to justice.

The call by the UN committee on the rights of the child will add further pressure on the Saudis to rethink the four-year war in Yemen.

In the US, a cross-party group of senators have urged the US secretary of state, Mike Pompeo, to rethink his decision to certify that arms sales can go ahead because Saudi Arabia is taking steps to protect civilians. The senators say the judgment is impossible to reconcile with the known facts, including the recent increase in the death toll.

It is possible that wider controversy over the alleged Saudi killing of the journalist Jamal Khashoggi will swell the number of US lawmakers demanding their country end its support for the war in Yemen.

The Saudis say they have been locked in a war since 2015 to oust Iranian-backed Houthi rebels that have dislodged the UN-recognised government. A fresh Saudi military offensive is under way after UN-sponsored peace talks in Geneva failed to get off the ground last month.

The latest UN report from a 15-strong panel in Geneva found that since March 2015 at least 1,248 children have been killed and the same number injured, amounting to about 20% of the total deaths and injury since the war began.

The report condemns “the dramatic consequences for civilians, and particularly for children who are being killed, maimed, orphaned, and traumatised, of military operations, aggravated by an aerial and naval blockade that has rendered many millions of people, including a high proportion of children, food insecure”.

It says the independent assessments undertaken by Saudis of their air raids are “insufficiently independent, lack detail and have no mechanism for enforcement”.

The panel said: “There has been no case, let alone a case involving child casualties, recruitment or use of children in armed hostilities, where its investigations led to prosecutions and/or disciplinary sanctions imposed upon individuals, including military officials.”

All allegations of unlawful attacks on children should be pursued effectively and the perpetrators brought to justice with appropriate sanctions, in order to prevent and fight against impunity, they added.