Palestinian prisoner Nasser al-Shawish was transferred from the Gilboa Prison to the hospital after suffering a stroke on Saturday evening, according to Palestinian media.
Shawish was arrested in 2002 and received a sentence of four life sentences for being behind a number of suicide bomber attacks.
The Palestinian Commission of Detainees' Affairs stated that it holds the Israeli government and Israel Prison Service responsible for Shawish's life and called for a visit by the commission's lawyer to be facilitated, according to the Palestinian WAFA news agency.
The commission's legal team is working to find out where Shawish was transferred to.