Belgium said on Thursday that it would summon Israel's ambassador to explain the killing in a Gaza airstrike of an aid worker with its Enabel development agency, as well as members of his family.
"Bombing civilian areas and populations is contrary to international law. I will summon the Israeli ambassador to condemn this unacceptable act and demand an explanation," Foreign Minister Hadja Lahbib said on social media platform X.
Her ministry said on X that Belgium "condemns the killing" of an Enabel employee and his son "by an Israeli bombardment".
Enabel said in a statement that Abdallah Nabhan, 33, along with his seven-year-old son, 65-year-old father, 35-year-old brother and six-year-old niece, were killed "after an Israeli airstrike in the eastern part of the city of Rafah".
The family was located in a house where 25 people were sheltering, including people displaced by the Israeli military offensive in Gaza, Enabel said.
It said that Nabhan, who had worked on a Belgian development project helping young people find jobs, and his family were on a list Israel had of people eligible to exit Gaza, but that they were killed before being granted permission to leave.
Enabel's chief, Jean Van Wetter, called their deaths "yet another flagrant violation by Israel of international humanitarian law".
Israel's war on Gaza has so far killed at least 34,305 people, according to the strip's health ministry.
Belgium, which currently holds the EU presidency, is among the European countries most vocal in condemning Israel's war as disproportionately deadly for Palestinian civilians.
A Hamas-led attack on 7 October killed around 1,170 people in Israel, according to an AFP tally of Israeli figures.