President Joe Biden voiced strong criticism of Israel Tuesday following a strike that killed seven aid workers in Gaza, saying it has not done enough to protect such workers.

"Incidents like yesterday's simply should not happen. Israel has also not done enough to protect civilians," Biden said in a statement.

Biden said he was "outraged and heartbroken" by the death on Monday of the World Central Kitchen workers, adding that distributing aid in the Palestinian territory has been difficult "because Israel has not done enough to protect aid workers trying to deliver desperately needed help to civilians."

In a strongly worded statement Biden said Israel's investigation of the strike "must be swift, it must bring accountability, and its findings must be made public."

Biden and other US officials have expressed growing frustration with Israel as its unrelenting war against Hamas in the Gaza Strip in response to the October 7 Hamas attack sends civilian deaths soaring.

The seven staffers from the US-based food aid charity were killed when a strike hit their convoy in the Gazan town of Deir al-Balah.

Biden said the death of the aid workers was not a "stand alone incident." The United Nations says the war has left almost 200 aid workers dead.

"This conflict has been one of the worst in recent memory in terms of how many aid workers have been killed," Biden said in his statement.

He said the United States will continue to press Israel to let more aid into Gaza and to allow "an immediate ceasefire as part of a hostage deal."

Israel's army acknowledged on Wednesday it had committed a "grave mistake."

Israeli Defense Forces Chief of Staff Herzi Halevi, in a message posted on social media platform X, blamed "a misidentification — at night during a war in very complex conditions."