JERUSALEM (Ma’an) -- Palestinian prisoner Mahmoud Issa has been let out of solitary confinement after spending 13 years in the harsh detention, a detainees rights group said Thursday.

Fuad al-Khafsh of the Ahrar center for prisoners studies, credited the ongoing Palestinian prisoner hunger strike with securing Issa's transfer from isolation.

He said it meant the Israeli prison service was beginning to respond to the prisoners demands for better treatment and an end to punishing conditions like separation from family visits.

Prisoners also said late Friday that Israeli authorities moved detainee Walid Khaled Ali, 40, from his solitary confinement facility to the general area in Ofer prison.

Hundreds of Palestinians on hunger strike in Israeli jails said Friday they would shun vitamin supplements and prison clinics in an escalation of their mass protest against detention conditions.

Rights groups say around 2,000 prisoners are on hunger strike to demand improved conditions in Israeli custody, such as an end to solitary confinement and more family visits.

Administrative detainees have also challenged Israel's policy of indefinite detention without charge.

The fate of the hunger strikers has touched a raw nerve among Palestinians, with daily support rallies in the occupied West Bank and Gaza, and political leaders warning that Israel could face new violence should any prisoner die.

Dozens of Palestinians have gone on hunger strikes in tents put up in solidarity in the West Bank and Gaza Strip, which witnessed daily heavy attendance by residents and visitors from Arab and foreign countries.

Israel says all prisoners receive adequate medical attention, including in civilian hospitals if required.

A Prisons Service spokeswoman said there was no immediate sign of the hunger strike being stepped up.

Reuters contributed to this report.