Greta Thunberg has made an incendiary claim that she was made to "kiss the Israeli flag" while the activist was in detention.
The Swedish climate campaigner was among 437 activists, parliamentarians and lawyers detained after Israeli forces intercepted their humanitarian aid convoy.
The flotilla attempted to breach the 16-year maritime blockade of Gaza between Thursday and Friday.
Turkish activist Ersin Çelik, who took part in the Sumud flotilla, told local news: "They dragged little Greta [Thunberg] by her hair before our eyes, beat her, and forced her to kiss the Israeli flag. They did everything imaginable to her, as a warning to others."
Greta Thunberg was forced to 'kiss the Israeli flag' whilst in detention, according to witness accounts
|REUTERS
Ms Thunberg told a Swedish official, who visited her whilst in detention, that she was detained in a cell infested with bedbugs, with too little food and water.
Another embassy was informed by a separate detainee that they witnessed Thunberg being made to hold flags whilst photographs were taken.
The activist expressed concern about whether these images had been circulated.
Journalist Lorenzo D'Agostino, another flotilla participant, corroborated the accounts after returning to Istanbul.
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The Swedish climate campaigner was among 437 activists
|REUTERS
She described how Thunberg was "wrapped in the Israeli flag and paraded like a trophy" in scenes that provoked disbelief and anger amongst witnesses.
"She spoke of harsh treatment and said she had been sitting for long periods on hard surfaces," according to the Swedish ministry's email.
The majority of detained activists are being held at Ketziot prison in the Negev desert, a high-security facility typically used for Palestinian security prisoners whom Israel accuses of militant or terrorist involvement.
Israel's far-right national security minister, Itamar Ben-Gvir, visited Ashdod port on Thursday night, where he was filmed pointing at dozens of seated activists and calling them "terrorists" in Hebrew.
The flotilla attempted to breach the 16-year maritime blockade of Gaza between Thursday and Friday
|REUTERS
Legal representatives for the flotilla reported systematic violations of detainees' rights, with activists denied water, sanitation, medication and immediate access to lawyers, according to NGO Adalah.
The Israeli embassy categorically rejected the allegations as "complete lies", insisting all detainees received water, food, toilet access and legal counsel.
It said: "Israel is and will remain a state governed by the rule of law, committed to upholding the rights and dignity of all individuals in accordance with international standards."
This marks Thunberg's second arrest during attempts to break Gaza's naval blockade, following a similar incident earlier this year that ended in deportation.
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