Organisers of a Gaza-bound aid flotilla say freed foreign activists who were abducted from international waters, faced abuse while in Israeli detention, including at least 15 reporting incidents of sexual assault or rape.

The Global Sumud Flotilla organisers added in a statement on Telegram on Friday that several activists were hospitalised with injuries, a day after hundreds were deported from Israel.

Germany said some of its nationals who were on board the flotilla had been injured and that some ⁠accusations were “serious”, without giving further details. A legal source in Italy said prosecutors there were investigating possible crimes, including kidnapping and sexual assault.

Israeli forces abducted about 430 people on board 50 ships in international waters on Tuesday to halt a flotilla of volunteers trying to bring aid supplies to the Gaza Strip.

The allegations of abuse will add to pressure on Israeli authorities to explain the treatment of the detainees after a video was released by Israel’s far-right National Security Minister Itamar Ben-Gvir, which showed him taunting foreign activists at a makeshift holding pen in Israel’s city of Ashdod.

The activists are seen cable-tied and kneeling while Israel’s national anthem blares in the video, which was released on Wednesday.

‘Stripped, thrown to the ground, kicked’

“At least 15 cases of ‌sexual assaults, including rape. Shot with rubber bullets at close range. Tens of people’s bones broken,” organisers of the Global Sumud Flotilla posted on Telegram.

“While the world’s eye is trained on the suffering of our participants, we cannot emphasise enough that this is a mere glimpse of the brutality Israel imposes daily on Palestinian hostages.”

Luca Poggi, an Italian economist among those detained on board the flotilla, told the Reuters news agency on his arrival in Rome: “We were stripped, thrown to the ground, kicked. Many of us were tasered, some were sexually assaulted, and some were denied access to a lawyer.”

Ilaria Mancosu, an Italian activist, said the flotilla members were removed from their boats to two so-called prison ships. Those put on one of the ships suffered more violence than the other, she said. They were locked in a container and beaten by five soldiers, suffering fractures to the ribs and arms. Some had serious injuries to their eyes and ears caused by tasers.

Mancosu said they ⁠spent two days on the prison ships with no running water and used cardboard and plastic to keep warm at night since they had no blankets ⁠and were stripped of most of their clothes. Once on land, they were made to kneel for several hours and kicked and shoved if they moved or spoke. They were then taken to a prison where they were moved from room to room periodically to keep them from sleeping, she added.

Rome prosecutors are investigating the possible crimes of kidnapping, torture and sexual assault and will hear testimony from activists who have returned to Italy over the coming days, the Italian legal source told Reuters.

A ⁠German Foreign Ministry spokesperson said consular officials who met German activists on their arrival from Israel to Istanbul, Turkiye on Thursday, reported that a number had injuries and were undergoing medical checks.

Humane treatment of German nationals was an “absolute priority”, the spokesperson said, and “we naturally expect a full explanation, as some of the allegations that have been made are serious.”

Sabrina Charik, ⁠who helped organise the return of 37 French citizens from the flotilla, told Reuters that five French participants had been hospitalised in ⁠Turkiye, some with broken ribs or fractured vertebrae. Some had made detailed accusations of sexual violence, including rape, she said.

Israel’s prison service denies the allegations, and Al Jazeera was not able to verify any claims independently.

“The allegations raised are false and entirely without factual basis,” an Israeli prison service spokesperson said in a statement.

“All prisoners and detainees are held in accordance with the law, with full regard for their basic rights and under the supervision of professional and trained prison staff.”

In an Instagram post by an activist group, French national Adrien Jouen showed bruises across his back and on his forearms.

Activists said some of the alleged abuse took place at sea after their interception by Israeli naval forces, and some following their abduction and imprisonment in Israel.

Spain’s Foreign Minister Jose Manuel Albares told reporters that 44 Spanish ‌flotilla members were expected to arrive on Friday on flights from Istanbul to Madrid and Barcelona. Four of them had received medical treatment for injuries, he added.

A history of violent, deadly abductions

The flotilla movement emerged in 2006 during Israel’s war on Lebanon and expanded after Israel imposed its blockade on Gaza in 2007.

Since then, hundreds of vessels organised by international solidarity groups have attempted to reach the territory, carrying humanitarian aid and activists.

In 2008, two boats from the Free Gaza Movement became the first to successfully reach Gaza by sea despite the blockade.

In 2010, Israeli commandos stormed the Turkish ship Mavi Marmara; 10 activists were killed, and dozens were wounded.

Israeli forces have intercepted nearly every flotilla in international waters since that year.

Mistreatment allegations from activists who have been brought to Israel after naval interceptions have been common, and organisers say they fear sanctions and false accusations of Hamas links are being used to justify further crackdowns.