* Palestinian prisoners' hunger strike fuels protests
* Israeli troops, Palestinian protesters clash in West Bank
* Israeli official fears "things can get out of control"
Palestinian officials said on Sunday a Palestinian detainee who died in an Israeli prison was tortured before his death, but Israel said autopsy findings were preliminary and inconclusive.
The death of 30-year-old Arafat Jaradat in an Israeli jail on Saturday and a hunger strike by four inmates have flared tension across the occupied West Bank, where stone-throwing protesters clashed with Israeli soldiers on Sunday.
The Palestinian autopsy findings could further fuel unrest that has surged in the Palestinian Territories weeks before U.S. President Barack Obama is due to visit the region. Israel demanded the Palestinian Authority restore calm to the area.
Palestinian Minister of Prisoners Issa Qaraqea said Jaradat died as result of torture. The Palestinian Authority state pathologist was present at the autopsy on Jaradat's body, which was carried out in Israel.
"There were marks of torture on the back, marks of torture on the chest, a deep wound on the upper side of the shoulder, wounds alongside the spine and marks of torture underneath the skin," Qaraqea said, based on the Palestinian doctor's basic findings.
But Israel's Health Ministry said the injuries found in the autopsy could have been caused by the medical emergency team's efforts to resuscitate Jaradat.
It listed bruising on Jaradat's shoulder, chest and two elbows, as well as fractures in two of his right ribs.
"These initial findings are not enough to determine the cause of death," the Health Ministry said, adding that further test results were not yet in. An Israeli police spokesman said the investigation into Jaradat's death was still ongoing.
The Prisons Authority said on Saturday that Jaradat had not been on a hunger strike and had been examined by an Israeli doctor during an interrogation on Thursday.
Some 3,000 prisoners held a one-day fast on Sunday in protest of Jaradat's death, which Israel initially said was caused by a heart attack.
Israel demanded the Palestinian Authority stem the surge in protests but a senior aide to Palestinian President Mahmoud Abbas gave no indication the Authority, which exercises limited self-rule in the occupied West Bank, would issue any call for calm, and blamed Israel for the rise in unrest.
"Israel has conveyed to the Palestinian Authority an unequivocal demand to calm the territory," an Israeli government official said, adding the message was delivered by one of Prime Minister Benjamin Netanyahu's top aides.
As an apparent incentive to Palestinian leaders to intervene, Israel pledged to proceed with this month's transfer to the Authority of around $100 million in tax revenues that it collects on its behalf.
Israel began withholding the funds, money the Palestinian Authority badly needs to pay public sector salaries, after Abbas secured U.N. de facto recognition of Palestinian statehood in November.
In the latest clashes, hundreds of Palestinian protesters, in several towns and villages in the West Bank, hurled stones at Israeli soldiers, who responded with tear gas and stun grenades.
There were no reports of serious injuries in the confrontations, after a wave of violent protests last week in solidarity with the four hunger-striking prisoners.
Some 4,700 Palestinians are in Israeli jails, many of them convicted of anti-Israeli attacks and others detained without trial. Palestinians see them as heroes in a statehood struggle, and the death of any of the hunger-strikers would likely trigger widespread violence.
Prisoners affiliated with Hamas, the Islamist militant group that governs the Gaza Strip, issued a call for a new Palestinian uprising.
Abbas said in an Israeli television interview three months ago he would not allow a third armed Intifada to break out and that Palestinians would pursue their cause peacefully.
Amos Gilad, a senior Israeli Defence Ministry official, questioned whether the protests were just a tactical move by the Palestinians to draw international attention before Obama's visit to Israel, the West Bank and Jordan.
But he added, in an Israel Radio interview: "Things can get out of control."
Netanyahu has said Iran's nuclear programme would top the agenda of his meetings with Obama, but that the talks also would deal with Israeli-Palestinian peace efforts stalled since 2010.
Yasser Abed Rabbo, a senior Abbas aide, said Israel's treatment of prisoners and anti-Palestinian violence by Jewish settlers were "the cause of the deterioration".
The first Palestinian uprising began in 1987 and ended in 1993, when the Oslo interim peace accords were signed.
The second Intifada broke out in 2000 after the failure of talks on a final peace settlement. Over the following seven years, more than 1,000 Israelis died, half of them in suicide attacks mostly against civilians, and more than 4,500 Palestinians were killed by Israeli forces.