JERUSALEM, May 3 (Reuters) - Facing Israel's highest court in their wheelchairs, two Palestinian prisoners on the 66th day of their hunger strike appealed on Thursday for their release from detention without trial.

Thaer Halahla and Bilal Diab, suspected by Israel of security offences, are among at least 1,550 Palestinian prisoners refusing food in Israeli jails in a protest against so-called "administrative detention".

Among the prisoners currently on hunger strike, only Halahla, Diab and two other men have passed the 60-day mark. Ten stopped eating about 40 days ago while the others began the protest on April 17, Palestinian officials said.

Halahla, jailed for the past 22 months, told the three-judge Supreme Court panel hearing the appeal: "Administrative detention is a slow death."

"I want to live my life with dignity. I have a wife, and a daughter I never met. I am on hunger strike because there is no other way," he said.

A spokeswoman for Israel's Physicians for Human Rights said both Halahla and Diab, who live in the occupied West Bank, were in a "life-threatening" condition because of the length of their strike.

Sivan Weizman, a spokeswoman for the Israeli Prisons Authority, said the men were receiving proper medical care. "We are trying to talk to them to get them to eat. In the end, it's their choice," she said.

UNCONSCIOUS

Halahla and Diab looked gaunt and frail as they were wheeled into court. Ten minutes into the proceedings, Diab, 27, slumped unconscious and was removed from the chamber and taken back to an Israeli hospital.

The court deferred a ruling on the two prisoners' petitions. Their lawyer, Jawad Boulos, told Reuters he expected a decision next week, adding: "We are fighting a losing battle. As long as there is occupation, there will be detainees in Israeli prisons."

Israeli authorities say some 1,550 prisoners are on hunger strike. Palestinian sources give varying figures, all over 1,700.

There are more than 4,500 Palestinian prisoners in Israeli jails, most of them convicted of security-related offences. Some 320 of the prisoners are held in "administrative detention", a measure imposed by the Israeli military and which it defends as a means to avoid exposing confidential sources in court.

Two weeks ago, Israel released hunger striker Khader Adnan, a member of the militant Islamic Jihad movement, from jail amid concern he would die. He agreed to end his 66-day-long strike in exchange for a promise not to renew his detention.

Dubbed by Palestinian activists as "the battle of empty stomachs", the campaign has included solidarity marches in the West Bank and Gaza Strip.

Palestinians have demonstrated frequently outside an Israeli military court in the West Bank, hurling stones at Israeli soldiers who responded with tear gas, stun grenades and a foul-smelling liquid sprayed into the crowd.

The strikes have drawn a new wave of international criticism of Israeli policies.

"I am appalled by the continuing human rights violations in Israeli prisons and I urge the government of Israel to respect its international human rights obligations towards all Palestinian prisoners," said U.N. official Richard Falk, who monitors human rights in the Palestinian territories.

Israel declines to deal with Falk or even allow him into the country, accusing him of being biased.