The Israeli army said Wednesday it has closed its file on the deadly shelling of a UN school in Gaza during the 2014 war but other cases are still being investigated.

It did not give details of ongoing investigations but said three soldiers had been charged with looting and related offences.

Among the cases where no wrongdoing was found, it said in a 21-page report, was the shelling of a United Nations school in the southern Gaza town of Rafah in which 10 people died.

The attack was strongly condemned by UN Secretary General Ban Ki-moon, while the United States called it "disgraceful".

French President Francois Hollande said the bombing was "unacceptable" and called for those responsible to "answer for their actions".

The military report said that shortly before the incident three Palestinian fighters were spotted riding a motorcycle in Rafah.

A decision was made to make an air strike on them using a low-explosive missile to minimise damage to surroundings and after a sweep of the area showed no civilians in harm's way.

It said that after the missile was launched the men unexpectedly headed off a roundabout with multiple exits, toward the school gate.

"At the moment upon which the motorbike exited the traffic circle and started to travel along the road bordering the wall which surrounded the school, it was no longer possible to divert the munition which had been fired at the motorbike," the English-language document said.

"The strike on the motorbike riders occurred immediately after the motorbike passed by the gate of the school," it added. "Three (Palestinian) military operatives were among the fatalities."

The report said the Military Advocate General's examination concluded that proper procedures were followed.

"MAG found that the targeting process in question accorded with Israeli domestic law and international law requirements," it wrote.

"The decision to strike was taken by the competent authorities, and the object of the attack was lawful -- military operatives."

- 'Regrettable' that civilians harmed -

The July-August 2014 war between Israel and Gaza militants killed more than 2,200 Palestinians and 73 people on the Israeli side, and destroyed or damaged thousands of homes in Gaza.

A United Nations commission of inquiry announced in June 2015 it had received "credible allegations" that both sides had committed war crimes.

Israel's own report, published a week before, defended its conduct in the fighting as both "lawful" and "legitimate".

It acknowledged that "numerous civilians were caught in the hostilities" but added that Israel "did not intentionally target civilians or civilian objects".

The Palestinians have signed up to the International Criminal Court to pursue charges against Israel, and several rights groups have accused it of using indiscriminate force against civilians and residential buildings, including UN facilities.

They also accused Hamas of exploiting the fighting to execute Palestinian rivals and alleged Palestinian armed groups committed war crimes with "indiscriminate" rocket fire.

Wednesday's military report said investigators had also found no criminal conduct regarding a number of air strikes on residential buildings.

In one case it cited media reports that seven members of the Ziyadeh family died in a raid on Bureij refugee camp in central Gaza.

It said the target building "was being used as an active command and control centre by the Hamas terror organisation" and militants inside were engaged at the time in activity endangering troops in the area.

"Among the casualties were three military operatives in the Hamas and Palestinian Islamic Jihad terror organisations, who were members of the Ziyadeh family, as well as the senior military operative... Mohammed Muqadama," the army said.

"The fact that, in practice, civilians who were uninvolved in the hostilities were harmed, is a regrettable result, but does not affect the legality of the attack ex post facto," it wrote.