Damage is seen inside a hospital operated by Medecins Sans Frontieres after it was hit by a Saudi-led coalition air strike in the Abs district of Hajja province, Yemen August 16, 2016. REUTERS/Abduljabbar Zeyad

DUBAI (Reuters) - An investigative body set up by the Saudi-led coalition fighting in Yemen said on Tuesday it should apologize for a deadly attack on a Medecins Sans Frontieres (MSF) hospital in August that the group said killed 11 people.

But the Joint Group to Assess Incidents found the coalition was not responsible for or had legitimately targeted fighters in four other incidents that rights groups blamed on Saudi-led bombings and together killed dozens of people.

A Saudi-led military coalition intervened in a civil war in Yemen in March 2015 and has launched thousands of air strikes against the Iran-allied Houthi movement.

The campaign aims at restoring the internationally recognized government of Yemen back to power from Saudi exile but has failed to dislodge the Houthis from the capital Sanaa.

Regarding the attack on the MSF hospital, the investigators wrote: “The coalition forces must extend an apology for this unintentional mistake and provide the proper assistance to the families with affected persons.”

Rights groups say the attacks on clinics, schools, markets and factories may amount to war crimes. At least 10,000 people have been killed during Yemen’s war, according to the U.N.

The findings, presented at a news conference in the Saudi capital Riyadh, bring up to 15 the number incidents which the body has probed and largely defended coalition actions.

Either by denying that the alliance carried out the attacks or citing the presence of fighters in the area, the Joint Group has said the coalition has mostly acted legitimately to reduce civilian casualties.