(Reuters) - A Palestinian held without trial by Israel agreed Tuesday to end his 66-day hunger strike after Israeli authorities promised to release him in April in a deal that avoided judicial review of the detention policy.

Khader Adnan, a 33-year-old member of the militant group Islamic Jihad, had been refusing food since mid-December and doctors had voiced fears about his deteriorating health.

"There is a deal. He will stop his hunger strike. They will not extend his administrative detention and he will be free on April 17," an Israeli Justice Ministry spokeswoman said.

Supporters of Adnan welcomed the deal as a symbolic victory over Israeli occupation of the West Bank and handed out candy in the streets of its administrative capital, Ramallah.

"He got all the world to stand in solidarity with the detainees through his heroic strike," said a neighbor, Mohammed Jaber. "He won against Israel and scored an achievement for Palestinian detainees."

Human rights activists said the outcome would not change Israel´s practice of "administrative detention" which allows it to hold suspects indefinitely.

LUKEWARM SUPPORT

Concern had been mounting that Adnan was on his deathbed, raising the prospect of a violent backlash against Israel.

Student blogger Jalal Abu Khater said that by Day 50 of the hunger strike the story "exploded especially on Twitter and Facebook" and followers numbered Adnan´s days without food.

But there were few demonstrations of support for him in the West Bank, bloggers say, because Adnan is with Islamic Jihad and not Fatah, the secular, mainstream Palestinian movement.

A Reuters photographer who managed to enter Adnan´s hospital room Tuesday saw him sitting up on his bed looking around, apparently fully aware and talking with his lawyer.

Hundreds of Palestinians cheered at a news conference held outside Adnan´s village home by lawyer Jawad Boulos.

"Khader confounded the Israeli court and security systems and forced the attorney´s office to agree to the deal we proposed," Boulos said. "His hunger strike was launched to achieve freedom and not to die."

West Bank officials said Adnan´s hunger strike was the longest staged by a Palestinian detainee. Jihadist supporters had warned of violent reprisals against Israel if he died.

NO CHARGES

Israeli Foreign Minister Avigdor Lieberman decried the deal.

"There was a wrongful decision today, to release this Jihad activist," Lieberman said, calling Adnan a "terrorist."

Israel has not accused Adnan of direct involvement in terrorist attacks. He was not charged with any crime. The reasons for his detention were kept secret, other than a brief Israeli army statement saying he was arrested on December 17 for "activities that threaten regional security."

As the deal for his release was announced, Israel´s High Court cancelled at the last minute an appeal hearing, avoiding a high- profile examination of the controversial practice of detention without trial.

The court has upheld the procedure for decades, siding with the government´s argument that detention without trial is a necessary security measure that can be used to avoid exposing confidential information in trials.

The European Union´s foreign policy chief, Catherine Ashton, issued a statement Saturday repeating "the EU´s long-standing concern about the extensive use by Israel of administrative detention without formal charge."

Ayman Karaja of the Palestinian Addameer Prisoner Support and Human Rights Association said Israel was currently holding 310 Palestinians without trial. Some were detained under the measure even after serving prison terms of several years.

"The end of Khader Adnan´s case, regardless of the outcome, obviously will not end Israel´s policy of administrative detention because it is part of Israel´s bigger policy of punishing the Palestinian detainees," Karaja said.

(Additional reporting by Ali Sawafta, Allyn Fisher-Ilan and Maayan Lubell; Writing by Douglas Hamilton; Editing by Robin Pomeroy) (© Thomson Reuters 2012. 02/21/12)