An apparent Israeli airstrike killed six international aid workers with the World Central Kitchen and their Palestinian driver, the charity said on Tuesday, in a potentially major setback to efforts to deliver aid by sea to Gaza, where Israel’s offensive against Hamas has pushed hundreds of thousands of Palestinians to the brink of starvation.

The food charity, founded by celebrity chef Jose Andres, said it was immediately suspending operations in the region. The source of the fire late on Monday could not be independently confirmed.

Israeli Prime Minister Benjamin Netanyahu acknowledged that Israeli forces carried out the strike. In a statement on Tuesday, he said: “Unfortunately over the last day there was a tragic incident of an unintended strike of our forces on innocent people in the Gaza Strip.”

He said officials are “checking this thoroughly” and “will do everything for this not to happen again”.

The Israeli military expressed “sincere sorrow” over the deaths of seven aid workers killed in a strike in Gaza while stopping short of accepting responsibility.

Rear Admiral Daniel Hagari said on Tuesday that officials are reviewing the incident at the highest levels. He says an independent investigation will be launched that “will help us reduce the risk of such an event from occurring again”.

Footage showed the bodies, several wearing protective gear with the charity’s logo, at a hospital in the central Gaza town of Deir al-Balah. Those killed include three British nationals, an Australian, a Polish national and an American-Canadian dual citizen, according to hospital records. The charity said the team was travelling in a three-car convoy that included two armoured vehicles.

“Despite coordinating movements with the (Israeli army), the convoy was hit as it was leaving the Deir al-Balah warehouse, where the team had unloaded more than 100 tons of humanitarian food aid brought to Gaza on the maritime route.”

Erin Gore, the CEO of the charity, said: “This is not only an attack against WCK, this is an attack on humanitarian organisations showing up in the most dire of situations where food is being used as a weapon of war. This is unforgivable.”

Three aid ships from Cyprus arrived earlier on Monday carrying some 400 tons of food.