A Palestinian prisoner held in an Israeli jail and on hunger strike for 53 days is in a critical condition and could die "at any moment", his lawyer said Saturday.

"Khader Adnan may suddenly die at any moment, doctors have confirmed to me," Jawad Boulos, legal counsel for the Ramallah-based Prisoners Club told AFP.

He said he received a call in the middle of the night saying "that the doctors at the Israeli hospital, where Khadar Adnan is currently held, were on alert due to the deterioration of his condition".

Boulos said he made a bedside visit to his client on Saturday morning and found him "in a more critical condition, incapable of moving".

Israel Prisons Service spokeswoman Sivan Weizman said Adnan was receiving treatment in Assaf Harofeh hospital near Tel Aviv, but she could not comment on his medical condition.

Adnan is being held in "administrative detention", a procedure under which Israel imprisons Palestinian suspects without trial indefinitely for renewable six-month periods.

He was arrested as part of an Israeli mass roundup shortly after last June's kidnapping and murder of three Israeli teenagers in the occupied West Bank.

Israel blamed the killings on the militant Palestinian Hamas, but although the Islamist movement hailed the attack, it said the killers acted independently.

Earlier this month Hamas called for the immediate release of Adnan, who is protesting against the conditions of his imprisonment, according to the Palestinian Prisoners Club. (ren) (+++)