RAMALLAH, June 6 (Xinhua) -- Israeli prison guards attacked Palestinians held at Ramon prison in southern Israel Wednesday, leaving several detainees with bruises and difficulties in breathing, a Palestinian official said.

Eissa Qaraqe', the Palestinian minister of prisoners affairs, said the Israeli forces broke into the fourth section of the prison, where 120 prisoners are held.

"They beat the prisoners with batons," he told Voice of Palestine radio, adding that the guards fired tear gas after clashes and scuffles heightened and several prisoners suffered from injuries caused by the gas.

The prisoners set fire to their belongings in protest of the raid.

Israel holds about 3,500 Palestinians in 17 prisoners and detention facilities. Dozens of the inmates have been imprisoned for more than 25 years.

On Tuesday, Israel released a Palestinian prisoner who had been on a hunger strike for 78 days in protest of being held without a charge.

However, Israel refused to release another two prisoners who have been fasting for 82 days and 56 days respectively.

The prisoners are protesting mainly the administrative detention, which allows Israel to hold them for renewable terms without a charge.

In May, about 1,500 prisoners suspended their fasting after Egypt brokered a deal meeting the prisoners' demands.