Nine members of the Gaza aid flotilla arrived home in Switzerland on Sunday after being deported by Israel, with some alleging they had been subject to inhumane conditions whilst in detention there, the group representing them said.
Israel did not immediately comment on the new allegations. Its foreign ministry previously described reports that detainees had been mistreated as "complete lies".
Nineteen Swiss nationals, including the former mayor of Geneva Remy Pagani, were aboard boats in the flotilla of dozens of vessels that tried to deliver aid to Israeli-blockaded Gaza.
They were taken into custody on Wednesday by Israeli forces who intercepted the flotilla at sea and taken to Israel's Ktzi'ot prison, according to the Waves of Freedom flotilla group.
Nine of the group returned to Geneva on Sunday afternoon.
"The participants condemned the inhumane detention conditions and the humiliating and degrading treatment they suffered upon their arrest and incarceration," a statement by the group said.
Israel said on Sunday that the legal rights of the activists were being "fully upheld", that no physical force was used and all detainees were given access to water, food, and restrooms.
Detainees described conditions of sleep deprivation, lack of water and food, as well as some being beaten, kicked, and locked in a cage, the statement added.
Waves of Freedom said it is "deeply concerned" about the ten Swiss nationals who remain detained by Israel.
On Sunday, the Swiss Embassy in Tel Aviv visited the ten Swiss nationals in prison to provide consular protection.
"All are in relatively good health, given the circumstances," it said in a statement, adding it is doing everything possible to ensure their prompt return.
The Waves of Freedom said some have gone on hunger strike and appear weakened.
Hundreds of other activists including Swedish campaigner Greta Thunberg were also detained in what was the latest attempt by activists to challenge Israel's naval blockade of Gaza, where it has been waging war since Hamas' October 2023 attack.
