TEL AVIV—A Palestinian militant jailed for more than two months without trial forced Israel to agree Tuesday to release him after a hunger strike spurred concern about unrest in the West Bank if he should die.

Khader Adnan, a member of Islamic Jihad, deemed a security threat by Israel, ate after abstaining for 66 days, a protest that turned him into a cause célèbre among Palestinians and among human-rights activists.

Mr. Adnan´s petition to Israel´s Supreme Court had highlighted Israel´s controversial use of administrative detention, a decades-old emergency provision permitting the imprisonment of Palestinians from the West Bank and Gaza without a formal indictment or trial.

But hours before a High Court hearing Tuesday that was moved up because of his medical condition, Israel relented by reaching an agreement with Mr. Adnan´s lawyers allowing him to go free April 17 in return for ending the hunger strike.

Defending Israel´s actions, an official there said Mr. Adnan has been jailed seven times for his involvement in an Iranian-backed organization considered a terrorist group by the U.S., Canada and Israel.

But the official said there was concern about the fallout if Mr. Adnan died. Israel also faced protests from foreign governments and other groups.

"We faced a serious dilemma,´´ the Israeli official said.

Palestinians demonstrating in solidarity with Mr. Adnan clashed with Israeli soldiers Tuesday outside the West Bank city of Ramallah.

Palestinians and Israeli rights activists said it was the first time they could recall Israeli authorities being pressured into committing to end a term of administrative detention.

Mr. Adnan´s four-month term was scheduled to end May 8, but Israeli military courts could have renewed the administrative detention for an additional time period. Israel´s justice minister said it agreed to shorten the term to account for the weeks he was detained in interrogations by security authorities.

"It´s an interesting development,´´ said Kadoura Fares, a former Palestinian cabinet minister who helped fund the legal aid for Mr. Adnan. "Just a couple of days ago, he was considered a dangerous prisoner who couldn´t be released. Now they´re saying that he´s not dangerous.´´

Israeli Foreign Minister Avigdor Lieberman criticized the decision to release Mr. Adnan, whom he called a terrorist.

Israel inherited the administrative-detention provision from when the country was under British control. It permits Israeli authorities to hold detainees for eight days before bringing them before a judge, and allows detention periods of six months.

Rights activists have called the measure an infringement on basic rights. (Copyright © Dow Jones & Company, Inc.) 02/22/12)