Palestinian prisoners refuse food over Israel's illegal detention policy

The open hunger strike seeks to pressure the Israeli prison administration as well as the government to end their controversial policy of detention without charge or trial, the statement added.

Kayed, 35, had been due for release on 15 June after serving a nearly 15 year sentence for activities in the Popular Front for the Liberation of Palestine, considered a terrorist organisation by Israel.

Israeli authorities ordered that he remains in custody under the administrative detention law, which allows prisoners to be held without trial for renewable six-month periods.

Last week, the Palestinian detainee affairs commission head Issa Qaraqe said Kayed was suffering from failing kidneys and that he had lost about 30 kilos [65 pounds].

He was taken to hospital for treatment but remains in a critical condition, Ma'an news agency reported.

Qarage stressed that administrative detention is in violation of international law and humanitarian conventions.

Administrative detention is intended by Israel to allow authorities to hold suspects while continuing to gather evidence, however the system has been criticised by Palestinians, human rights groups and members of the international community.

Of more than 7,000 Palestinians currently in Israeli jails, around 750 being held under administrative detention, Palestinian rights groups Addameer said.

Palestinians have regularly gone on hunger strike in protest at their detention.

Agencies contributed to this report.