PARIS -- The United States and Britain led international criticism Tuesday of a deadly strike in the Gaza Strip that killed seven charity staff as they unloaded desperately needed aid brought by sea to the war-torn territory. World Central Kitchen -- one of two NGOs spearheading efforts to deliver aid by boat -- said a "targeted Israeli strike" on Monday killed Australian, British, Palestinian, Polish and US-Canadian staff.

Washington, Israel's main ally, said it was "heartbroken and deeply troubled by the strike." "Humanitarian aid workers must be protected as they deliver aid that is desperately needed," US National Security Council spokesperson Adrienne Watson wrote on X, formerly Twitter.

Israel's Prime Minister Benjamin Netanyahu said the strike was "unintentional." The Israeli army has vowed to hold an investigation and promised to "share our findings transparently." British Foreign Secretary David Cameron -- who has been increasingly critical of Israel's war in Gaza -- said the country had "called on Israel to immediately investigate and provide a full, transparent explanation of what happened."

UK Prime Minister Rishi Sunak said he was "shocked and saddened" after learning that a Briton was among those killed.

Australian Prime Minister Anthony Albanese slammed the "completely unacceptable" attack, and called it a "tragedy that should never have occurred."

He offered "sincere condolences" to the family of Australian volunteer Lalzawmi "Zomi" Frankcom, who was killed in the strike. "She just wanted to help out through this charity. That says everything about the character of this young woman," Albanese said.

'Indiscriminate killing'

The founder and leader of World Central Kitchen, celebrity chef Jose Andres, said he was "heartbroken and grieving for their families and friends and our whole WCK family."

"The Israeli government needs to stop this indiscriminate killing," he wrote on social media. "It needs to stop restricting humanitarian aid, stop killing civilians and aid workers, and stop using food as a weapon."

The charity said it had coordinated its movements with the Israeli army and was travelling in vehicles branded with its logo.

It has paused its operations in Gaza. The EU's foreign policy chief Josep Borrell said that "despite all the demands to protect civilians and humanitarian workers, we see new innocent casualties."

"I condemn the attack and urge an investigation," he wrote on X.

Warsaw said it had asked the Israeli ambassador for "urgent explanations" about the incident, which killed one Polish citizen, and offered "condolences to the family of our brave volunteer." Polish Foreign Minister Radoslaw Sikorski said the country had also opened its own inquiry into the aid worker's death.

Criticism also came from Beijing, which said it was "shocked" by the strike, and from Madrid, where Prime Minister Pedro Sanchez called it a "brutal attack that has taken the lives of seven aid workers who were doing nothing but helping."

Since Hamas's October 7 attacks triggered the war, Gaza has been under a near-complete blockade, with the United Nations accusing Israel of preventing deliveries of humanitarian aid. (AFP)