A missile struck a petrol station near the entrance to Kitaf rural hospital, about 100km from the city of Saada in the northwest of the country, at 9.30am.

The hospital had been open for only half an hour and many patients and staff were arriving on a busy morning. They included a health worker who died along with their two children.

Also among the dead were two other children and a security guard. In addition to those killed and missing, a further eight people were wounded in the attack.

The missile was said to have landed within 50 meters of the facility’s main building on the fourth anniversary of the escalation of conflict in Yemen.

Save the Children, which reported earlier this week that 37 children a month had been killed or injured by foreign bombs in the last year, demanded an urgent investigation into the latest atrocity.

Helle Thorning-Schmidt, the chief executive of Save the Children International, who visited Save the Children health facilities in Yemen last year, said: ‘We are shocked and appalled by this outrageous attack. Innocent children and health workers have lost their lives in what appears to been an indiscriminate attack on a hospital in a densely populated civilian area. Attacks like these are a breach of international law.

‘This hospital is just one of the many Save the Children support across Yemen, delivering life-saving aid to children living in what is the worst place on earth to be a child. These children have the right to be safe in their hospitals, schools and homes. But time after time, we see a complete disregard by all warring parties in Yemen for the basic rules of war. Children must be protected. We must Stop this War on Children.”

Save the Children, which covers some of the staff costs at the hospital, is calling for an immediate suspension of arms sales to warring parties in Yemen, where children continue to be killed and maimed indiscriminately.

It is also calling for full diplomatic pressure to be applied to all parties in the conflict to resolve it through consultation and negotiation, and for those who commit violations of international law to be held to account.

For more information or to arrange interviews, please contact: media@savethechildren.org.uk / +44 (0)20 7012 6841 / +44 (0)7831 650409 (out of hours)