Pro-Palestinian activists deported by Israel after their Gaza-bound aid flotilla was intercepted in international waters have alleged extensive abuse in Israeli custody, with the flotilla’s organisers claiming “at least 15 cases of sexual assaults” and detainees describing beatings and dehumanisation.

The Global Sumud Flotilla (GSF), more than 50 boats that set out from Turkey last week to breach Israel’s maritime blockade of Gaza, was boarded by Israeli commandos west of Cyprus on Monday and Tuesday. Detained activists were taken to a prison via Ashdod port; 422 people from 41 countries were deported on Thursday.

Canadian Foreign Minister Anita Anand said her officials had detailed “appalling abuse” of Canadian detainees and that “those responsible for this egregious abuse must be held accountable.” A German foreign ministry spokesperson said consular officials met returning activists in Istanbul and reported a number were injured. Spanish Foreign Minister José Manuel Albares said four of 44 Spanish activists had received medical treatment.

Adalah, an Israel-based rights group representing detainees, said its lawyers received “a large number of complaints of extreme violence” at Ashdod port and that at least three people were hospitalised. Italian MP Dario Carotenuto and journalist Alessandro Mantovani told reporters in Rome about beatings at a detention facility built from shipping containers. British activist Richard Johan Anderson said at Istanbul airport: “We’ve been beaten, tortured, systematically dehumanised.”

Israel’s prison service dismissed the allegations as “entirely without factual basis,” saying detainees were held “in accordance with the law.” The accounts followed earlier criticism of National Security Minister Itamar Ben Gvir over a video showing kneeling activists, conduct Prime Minister Benjamin Netanyahu publicly called “not in line with Israel’s values.”

Sri Lankan national Sameera Mehboobdeen, who was deported via Istanbul on Thursday, was among those held during the operation that began when Israeli commandos intercepted the Global Sumud Flotilla on May 18.