Swiss and Spanish activists from an international flotilla that tried to deliver aid to Gaza last week said they faced "inhumane conditions" during their detention by Israeli forces.

Among the nine members of the flotilla who arrived home in Switzerland, some alleged sleep deprivation, lack of water and food, as well as being beaten, kicked, and locked in a cage, the group representing them said in a statement.

Spanish activists also claimed mistreatment upon their arrival in Spain late on Sunday after being deported. "They beat us, dragged us along the ground, blindfolded us, tied our hands and feet, put us in cages, and insulted us," lawyer Rafael Borrego told reporters at Madrid's airport.

Israel's Minister of Justice, Yariv Levin, announced on Monday that 170 flotilla activists have been deported. Of the 309 still in custody in Israel, 200 are expected to be expelled within the next 24 hours.

Swedish activists on Saturday claimed that climate campaigner Greta Thunberg was shoved and forced to wear an Israeli flag during her detention. In contrast, others reported that they had their food and water withheld, and their medication and belongings confiscated.

Israel's foreign ministry called widespread reports of detainee mistreatment after the flotilla was intercepted "complete lies." A spokesperson stated over the weekend that all detainees received access to water, food, and restrooms, and added: "They were not denied access to legal counsel and all their legal rights were fully upheld.”

A Spanish detainee bit a female medical worker at Ketziot Prison during a routine exam before her deportation, causing minor injuries treated on site, the ministry said.

On Sunday, the Swiss Embassy in Tel Aviv visited the ten Swiss nationals still being held in custody and stated all were "in relatively good health, given the circumstances." It also mentioned that it was doing everything possible to ensure their swift return.

Former Barcelona Mayor Ada Calau, who was also on the flotilla, said there had been "mistreatment, but that was nothing compared to what the Palestinian people suffer every day."

Consular staff have visited activists at the prison, according to statements from several countries whose citizens were detained. More activists are expected to be released on Monday and transported to Athens.