Nearly 4000 Palestinian prisoners in Israeli jails are on hunger strike to protest against the death of fellow prisoner at the weekend.
The prison service said Arafat Jaradat, 30, died of a heart attack, but human rights groups dispute this.
The BBC reports he was arrested last week on suspicion of throwing stones at Israeli soldiers.
Human rights groups suggested Mr Jaradat died either during or shortly after interrogation.
On Sunday, Mr Jaradat's body underwent an autopsy attended by a Palestinian pathologist.
A preliminary statement said that "no signs of external injury were found apart from marks of resuscitation and a small friction on the right side of the chest".
There was also a series of clashes between Palestinians and Israeli security forces in the past three days.
CNN reports police in Hebron fired stun grenades at demonstrators who were throwing stones in protest at the conditions of Palestinians on an extended hunger strike.
The Palestinian Prisoners Club said the number of inmates on open-ended hunger strike has climbed to 11 from four.
As of December 2012, Israel held 4517 Palestinians in its prisons; 170 are under 18 years of age.