"Our munition alone could not have ignited a fire of this size," Hagari said in a press briefing on the preliminary findings of an army probe into the deadly blaze that has drawn international condemnation.

Israel's military said it targeted and killed two senior Hamas militants in northwest Rafah in Sunday's strike, which sparked a blaze that tore through an encampment full of displaced Palestinians.

On Monday, Prime Minister Benjamin Netanyahu called the incident "a tragic accident".

Hagari said that "based on precise intelligence", aircraft dropped two 17-kilogramme munitions on the target, which he added was away from tent shelters housing displaced civilians.

"We are looking into all possibilities, including the option that weapons stored in a compound next to our target... may have ignited as a result of the strike."

Hagari then aired a recording of a phone call he said Israeli intelligence intercepted, which raised "the possibility that weapons stored in a nearby compound caught fire".

"Despite our efforts to minimise civilian casualties, the fire that broke out was unexpected and unintended," he said, adding the incident was still under investigation.