An Israeli tank strike on a United Nations guest house in central Gaza has left a European aid worker dead and five others injured, according to a Washington Post investigation that raises fresh concerns over the safety of humanitarian personnel and the growing impunity surrounding attacks on protected sites.

The incident occurred on 19 March, just one day after Israel resumed its military offensive following a brief ceasefire. Fifty-one-year-old Bulgarian national Marin Marinov, a staff member of the UN Office for Project Services (UNOPS), was killed as two tank shells struck the guest house while aid workers were inspecting previous damage. The first shell exploded outside the building; the second detonated inside, after penetrating an upper wall.

Analysis of shell fragments and aftermath images by munitions experts confirmed the use of Israeli M339 rounds, armour-piercing shells specifically designed to explode inside structures. These rounds are only fired from Israeli Merkava tanks, and no other military force operating in Gaza possesses or uses this munition.

Despite repeated communication of the facility’s coordinates to Israeli forces, the guest house—clearly marked as a humanitarian site—was still targeted. Satellite images reviewed by the Post showed Israeli tanks and armoured vehicles within striking distance of the guest house the day before the attack.

UN spokesperson Stéphane Dujarric expressed outrage and demanded accountability: “Whether this was intentional or a tragic mistake, those responsible must be held to account.” He added that Israel had been fully informed of the guest house's location.

Marinov’s death brings the total number of UN staff killed in Gaza since the start of the war to more than 280. Humanitarian groups warn that such attacks are part of a disturbing pattern of disregard for international law. The UN has since withdrawn a third of its international staff from Gaza, citing unbearable risks under ongoing bombardment and siege conditions.

As the death toll in Gaza surpasses 50,000, the targeting of aid workers only deepens the humanitarian catastrophe and underscores the urgent need for international intervention to protect civilians and enforce the laws of war.