The UN Coordinator for Humanitarian Assistance and Development Aid in the occupied Palestinian territory Robert Piper said he was “deeply concerned” about the declining health of hunger striking Palestinian prisoners protesting their administrative detention and called on Israel to release or charge all detainees “without delay.”

“I am deeply concerned about the deteriorating health of Palestinian detainee Bilal Kayid, after 67 days of a hunger strike protesting his detention without charge or trial,” Piper said in the statement released by the UN agency on Saturday.

“This is an egregious case, in which Mr. Kayid was placed on administrative detention on the day of his scheduled release after completing a 14.5 year prison sentence.”

He highlighted the fact the some 100 Palestinian prisoners held in Israeli prisons across the country have since launched hunger strikes in solidarity with Kayid against administrative detention and prolonged solitary confinement, including prominent Palestinian journalist Omar Nazzal.

“The number of administrative detainees is at an eight-year high. I reiterate the United Nations long-standing position that all administrative detainees — Palestinian or Israeli — should be charged or released without delay.”

Israel’s controversial policy of administrative detention is used primarily against Palestinians, who are held without trial or charge for renewable periods of six-months at a time.

Piper’s statement came amid reports that an Israeli Supreme Court hearing is to be held Monday over the release of Kayid from his administrative detention sentence, as the head of the Palestinian Committee of Prisoners’ Affairs Issa Qaraqe warned the hunger strikers health was “a ticking time bomb.”