Belgium on Tuesday joined South Africa in a case brought before the International Court of Justice (ICJ), which accuses Israel of committing genocide in the Gaza Strip.
The UN's highest court, based in The Hague, said in a statement that Brussels had filed a declaration of intervention.
Several countries including Brazil, Colombia, Ireland, Mexico, Spain and Turkey have already joined the case.
In December 2023, South Africa brought a case to the United Nations' highest court in The Hague, alleging Israel's Gaza offensive breached the 1948 UN Convention on the Prevention and Punishment of the Crime of Genocide.
Israel denies the accusation.
In rulings in January, March and May 2024, the ICJ told Israel to do everything possible to prevent acts of genocide in Gaza, including by providing urgently needed humanitarian aid to prevent famine.
These orders are legally binding, but the court has no concrete means to enforce them.
Israel has criticised the proceedings and rejected the accusations.
Hamas's October 7, 2023 attack resulted in the deaths of 1,221 people on the Israeli side, mostly civilians, according to an AFP tally based on official Israeli figures.
The Israeli military's retaliatory campaign has since killed 70,369 Palestinians, also mostly civilians, according to Gaza's health ministry, whose figures are considered reliable by the UN. The campaign has also displaced the majority of the 2.2 million people in the Palestinian territory.
Belgium was among a string of countries to recognise the State of Palestine in September, a status acknowledged by nearly 80 precent of UN members.
