An apparent Israeli airstrike killed four international aid workers with the World Central Kitchen charity and their Palestinian driver late Monday, hours after the group brought in a new shipload of food by a maritime route the United States has hoped would be an alternative lifeline for northern Gaza, isolated and pushed to the brink of famine by Israel’s offensive.

Footage showed the bodies of the five dead at Al-Aqsa Martyrs Hospital in the central Gaza town of Deir al-Balah. Several of them wore protective gear with the charity’s logo. Staff showed the passports of three of the dead – British, Australian and Polish. The nationality of the fourth aid worker was not immediately known.

The Israeli military said it was conducting a review “to understand the circumstances of this tragic incident.”