Two Israelis have been detained and questioned in Belgium as part of an investigation into war crimes in Gaza.
Two rights groups, the Hind Rajab Foundation and the Global Legal Action Network, said the pair were detained after the groups told Belgian authorities there was credible evidence they had committed war crimes in Gaza.
"The action came in response to an urgent legal complaint filed by the Hind Rajab Foundation and the Global Legal Action Network (GLAN) earlier this week," the Hind Rajab Foundation said in a statement.
Israel's Foreign Ministry confirmed two citizens on holiday in Belgium were briefly detained.
It did not say whether they were held due to the war crimes allegations, but Belgium's public broadcaster said the prosecutor's office confirmed they were detained because of the complaint.
The rights groups said Belgian authorities had opened a criminal investigation into the pair.
The Hind Rajab Foundation is a legal non-governmental organisation registered in Belgium. It is named after a five-year-old Gazan girl killed by Israeli forces in January, 2024, in what UN experts said was a possible war crime.
The group has been using the social media posts of travelling Israeli soldiers to track them and seek their arrests overseas using something called "universal jurisdiction", the legal principle that any state can try a person for a serious breach of international law, regardless of where the crime was committed.
'This action sends a clear message'
After the foundation began its campaign, the Israel Defense Forces released new restrictions on the media identifying its soldiers and told IDF members not to post about their actions in Gaza on social media.
The Hind Rajab Foundation and other legal groups have sought the arrest of Israeli soldiers around the world — causing some holidaying Israelis to flee a number of countries — but the group said this was the first time authorities actually detained anyone.
"This development is a significant step forward," it said in a statement.
"It signals that Belgium has recognized its jurisdiction under international law and is treating the allegations with the seriousness they deserve.
"At a time when far too many governments remain silent, this action sends a clear message: credible evidence of international crimes must be met with legal response — not political indifference."
The Israeli government has sought to discredit the Hind Rajab Foundation, saying the group is "anti-Israel" and accusing its founder, Lebanese-born Belgian activist Dyab Abou Jahjah, of sympathising with the Shia militant group Hezbollah, a listed terrorist organisation in many countries, including Australia.
Israel's Foreign Minister Gideon Saar has called the group a "gang of Holocaust deniers, supporters of abducting Israeli civilians, and admirers of [former Hezbollah leader] the late [Hassan] Nasrallah".
Pro-Israel politicians in Belgium sought to have the group de-registered but in May the country's justice minister said a state security evaluation had found no concrete evidence of links to Hezbollah or of any threat to the Belgian state.
Dyab Abou Jahjah has previously responded to the Israeli allegations by saying he was never a member of Hezbollah and does not agree with the group's ideology.