JERUSALEM – A Palestinian rights group said Monday that half of about 5,000 Palestinian prisoners held by Israel are on a hunger strike, demanding an end to imprisonment without trial as well as better conditions.

Ehteram Ghazawneh of the Palestinian group Addameer said prisoners object to "administrative detention" that incarcerates some of them for months or years without charges.

More than 300 Palestinians are held in administrative detention, where an Israeli military court allows imprisonment based on secret evidence. The rulings are periodically reviewed.

The Israeli military says it uses administrative detention to protect informants or when they fear an immediate risk to security. The military did not respond to requests for comment about the hunger strike.

Ghazawneh says prisoners also want to end solitary confinement and allow prisoners from Gaza to have family visits.

She estimated that 2,500 prisoners were participating.

Israeli prison service spokeswoman Sivan Weizman had different figures. She said that 1,450 are on a hunger strike. Of them, two prisoners have refused to eat for 63 days.

The strikers appear to be inspired by Khader Adnan, a spokesman for the violent Palestinian Islamic Jihad group, who refused food for 66 days before he was freed.

After Adnan, a Palestinian detainee went on a 44-day hunger strike to protest her detention. She was freed after agreeing to a deal that sent her to the Gaza Strip for three years.

Weizman said eight prisoners who had been on strike for over 40 days were being held in a medical facility, where they were receiving liquids.

The fate of prisoners held by Israel is one of the most emotional issues for Palestinians. They are generally seen as heroes, even when their crimes have involved killing Israeli civilians.

The two longest hunger strikers, Bilal Diab, 27 and Thaer Halahleh, 33, are both administrative detainees. Both belong to the militant group Islamic Jihad, a group which has carried out suicide bombings and other attacks, killing Israeli civilians.

Diab has been in administrative detention since August and Halahleh since June 2010, Ghazawneh said.

Israel does not give details of suspicions against administrative detainees. (© 2012 The Associated Press 04/30/12)