Israel's military has admitted killing a UN worker with tank fire in an incident in the Gaza Strip last month, having previously denied responsibility.
After Marin Valev Marinov, a Bulgarian employee of the UN Office for Project Services (UNOPS), was killed when a UN compound in Deir al-Balah was damaged on 19 March, the Israel Defense Forces (IDF) said it had not struck the site.
But the IDF said on Thursday that the initial findings of its investigation indicated its troops had in fact killed Marinov after wrongly identifying the building as containing an "enemy presence".
"The building was struck due to assessed enemy presence and was not identified by the forces as a UN facility," it added.
These preliminary findings have been shared with the UN and the full conclusion will also be provided, it said.
It added: "The IDF regrets this serious incident and continues to conduct thorough review processes to draw operational lessons and evaluate additional measures to prevent such events in the future.
"We express our deep sorrow for the loss and send our condolences to the family."
Bulgarian Foreign Minister Georg Georgiev said in a statement: "The Israeli side has apologised to Bulgaria."
He added: "Along with this, we will insist on fair compensation for Captain Marinov's relatives. In addition, we firmly call for such incidents not to be repeated."
Georgiev also stressed that the protection of the humanitarian workers was "of paramount importance".
The incident, which also seriously injured five other UN personnel, came a day after Israel renewed its offensive against Hamas after a two-month ceasefire collapsed.
At the time, UN Secretary General António Guterres called for a full investigation into the incident, while a spokesperson said: "The locations of all UN premises are known to the parties to the conflict, who are bound by international law to protect them and maintain their absolute inviolability."
Following the attack, the UN Office for Project Services (UNOPS) said that "explosive ordnance was dropped or fired" at a guesthouse, which was in an "isolated" location. Its executive director, Jorge Moreira da Silva, said it was "not an accident".
The IDF said in a statement on the day of the attack: "Contrary to reports, the IDF did not strike a UN compound in Deir al-Balah. The IDF calls on media outlets to act with caution regarding unverified reports."
Footage verified by the BBC showed injured people – two wearing blue UN flak jackets – arriving at a hospital in an ambulance and a UN car.
