Islamic Jihad-affiliated inmates started a three-day hunger strike on Thursday to show solidarity with Sheikh Khader Adnan, who has been on hunger strike for 49 days, prisoners said. Prisoners held at Israel's Eshel prison on Saturday told the Prisoners Center for Studies that prisoners threatened to announce an open hunger strike if the Israeli prison service will not respond to Adnan’s demands. They expressed worries about Adnan’s life and urged the prison service to cancel his administrative detention. Raafat Hamdouna, director of the center, called on the Palestinian people and organizations to carry out solidarity campaigns to free Adnan. He says Adnan lost 20 kilograms since he started his hunger strike. On Friday, minister of prisoners affairs Issa Qaraqe said detainees in Israeli jails launched a disobedience campaign to support Adnan, returning food, and refusing outdoor breaks and medical treatment. The prisoners have threatened to start an open hunger strike if Israeli prison authorities do not meet the demands of Adnan's protest, which began 50 days earlier, he said. The Jihad leader, who was detained from his Jenin-district home on Dec. 17, is protesting his treatment by Israeli prison authorities and the practice of detention without charge. On Jan. 8, Israel issued an administrative order to extend his detention for four months without trial or charge. Adnan is appealing the order, and appeared at a hearing in Ofer military court on Wednesday in a wheelchair, but a verdict has yet to be given. There are currently 280 prisoners in administrative detention -- without charge -- in Israeli jails.