United State President Joe Biden condemned the killing of seven aid workers in Gaza saying he was "outraged and heartbroken" over the deaths of the humanitarian workers.

The Israeli airstrike on the World Central Kitchen convoy killed citizens of Australia, Britain and Poland as well as Palestinians and a dual citizen of the United States and Canada, said the Hamas-run government's media office on Monday.

In a statement, Biden said: "I am outraged and heartbroken by the deaths of seven humanitarian workers from World Central Kitchen, including one American, in Gaza yesterday. They were providing food to hungry civilians in the middle of a war. They were brave and selfless. Their deaths are a tragedy."

The US President demanded that Israel conduct a swift investigation into the incident and bring accountability while making the findings public.

Biden also blamed Israel for "not doing enough" to protect aid workers "trying to deliver desperately needed help to civilians", attributing it as the "major reason why distributing humanitarian aid in Gaza has been so difficult."

Urging Israel to "deconflict their military operations against Hamas with humanitarian operations", Biden said, "Israel has also not done enough to protect civilians."

"I will continue to press Israel to do more to facilitate that aid. And we are pushing hard for an immediate ceasefire as part of a hostage deal," he said.

Biden also spoke with Chef José Andrés, the founder of World Central Kitchen to convey condolences for the deaths of the aid workers, the statement added.

Meanwhile, in the face of mounting calls for explanations and widespread condemnation by the US and other allies, Israeli Prime Minister Benjamin Netanyahu said that the airstrike "mistakenly" killed the aid workers, reported Reuters.

Israel's military voiced "sincere sorrow" over the incident which escalated the international pressure to ease the disastrous humanitarian situation in Gaza since the October 7 war which has killed at least 32,782 Palestinians in the besieged enclave.