- Arafat Jaradat had been detained for five days when he died
- Palestinian president says Israelis killed him
- Israeli officials say he had previous injuries, call for calm
- U.N. calls for transparent investigation into death
Tensions in the West Bank are heightened after the recent death in an Israeli prison of a 30-year-old Palestinian arrested last week.
Arafat Jaradat died Saturday, inciting Palestinian officials to once again decry conditions in Israeli prisons.
"The prisoner martyr Jaradat went to prison to come back a corpse, but we are determined to find out how it was done and who did it," Palestinian Authority President Mahmoud Abbas said Monday, according to the state news agency WAFA. "We know how we will act, and we will not let them (Israelis) drag us to their square, and they should bear the responsibility."
The United Nations weighed in Monday, calling for a thorough probe into Jaradat's death.
"The United Nations expects the autopsy to be followed by an independent and transparent investigation into the circumstances of Mr. Jaradat's death, the results of which should be made public as soon as possible," Robert Serry, the U.N. special coordinator for the Middle East peace process, said in a written statement.
Israel said doctors had worked to save the inmate, who was suffering from previous injuries. Palestinian officials said Jaradat was tortured.
Palestinians in Israeli prisons -- about 4,500 people -- took part in a hunger strike Sunday, and crowds protested in the streets of the West Bank as Palestinian officials called for an international investigation into an inmate's death.
Palestinian officials told CNN that Jaradat is the 203rd Palestinian to die in Israeli prisons since 1967.
He was buried Monday near his home in the West Bank as dozens of masked members of al-Aqsa Martyr's Brigade -- the armed wing of Fatah -- fired rifles in the air in protest.
"They killed him only in five days," his sister told Palestinian TV. "They kidnapped him from life. Oh, my dear little brother! Oh, my love!"
A Palestinian official sent a warning Sunday to U.S. President Barack Obama, who plans to make his first trip to Israel as president next month.
"If President Obama wants to visit the region peacefully, he should exert pressure on Israel to release the prisoners -- especially the ones who are on hunger strike -- or else he will visit while Palestine is on fire," Minister of Prisoner Affairs Issa Qaraqe said.
Israeli officials Sunday called on the Palestinian Authority to calm the territories, where there have been large protests in recent days over the conditions of Palestinian prisoners.
Israeli Prime Minister Benjamin Netanyahu's liaison with Palestinians, Yitzhak Molco, passed on the demand for calm to the Palestinian Authority, Israeli government officials said.
Jaradat's death came amid a fury -- and a series of questions -- surrounding the death of a prisoner in 2010, referred to as "Prisoner X." Details came to light in recent days after a court document was released.
Jaradat had been held for interrogation since Monday for a 2011 incident in which an Israeli citizen was injured by rock-throwing Palestinian protestors.
Jaradat confessed, Israeli security sources said.
Human Rights Watch called on Israel on Saturday to "immediately charge or release Palestinians detained without charge or trial for prolonged periods."
Palestinian prisoners in Israeli detention are one of many flashpoints in the Middle East conflict. Prisoners have launched hunger strikes in the past in hopes of bringing attention to their cause and pushing Israel to ease conditions or allow some prisoners to leave.
Israeli officials have said that prisoners include members of extremist groups who have "blood on their hands."
In October 2011, Israel freed more than 1,000 Palestinian prisoners -- including hundreds serving life sentences for attacks on Israelis -- in exchange for one person: Israeli soldier Gilad Shalit, who had been held by Hamas for more than five years.
"The United Nations appeals for maximum restraint by all parties to prevent further violence. The United Nations will continue engaging with the parties on the ground with a view to finding a solution that addresses the plight of prisoners and preserves the calm," Monday's U.N. statement said.