Over 100 Palestinian prisoners being held by Israel launched a hunger strike on Wednesday after they were moved against their will to another section of the Nafha jail in the Negev desert.
The 120 prisoners -- mostly affiliated with Fatah -- were moved from Section 10 of the jail to Section 41 last week without being allowed to take any of their belongings with them, the Prisoner's Center for Studies said.
Israel's prison administration had promised to return their belongings on Wednesday.
Earlier, Hamas-affiliated detainees in prisons across Israel threatened a campaign of disobedience Wednesday after the Israeli Prison Service said it plans to separate prisoners affiliated to Hamas in Nafha prison from those affiliated to Fatah, a prisoners' rights group said.
According to the Palestinian Prisoners Center for Studies, the Israeli prison authorities decided on Tuesday to move Hamas-affiliated prisoners from Nafha prison in southern Israel to Gilboa prison in the country's north.
The decision came after more than a week of trouble inside Nafha, where Palestinian prisoners began a campaign of disobedience last week to demand that the prison authorities end violations against them.
Prisoners in Nafha, Ramon, Eshel and Ofer jails declared a campaign of disobedience to protest a spate of cell raids and physical assaults by the Israeli prison authorities.