In a sprawling Israeli prison, Palestinian activist Hassan Karajeh sat through a hurried court hearing in a language he didn't understand under the authority of a military occupation he and his people reject.

The translator in the cramped portacabin-turned-courtroom seldom bothered to relay the military judge's words, and the tall, bearded detainee spent most of the time whispering to his family and blowing kisses to his young fianc?e.

Outside Ofer Prison's walls and throughout the West Bank, Israeli troops have clashed in recent weeks with Palestinian protesters fed up with Israeli detention policies, an emblem of what they see as Israel's unjust rule over their lives.

The violence raised concern in Israel that it could snowball into a third mass Palestinian uprising if either of two detainees on a months-long hunger strike dies, further burying hopes of reviving a long-stalled peace process.

Some 4,800 Palestinians are held in Israeli jails and are feted at home as political prisoners or freedom fighters. Israel says the majority are terrorists with blood on their hands, and some have pleaded guilty to killing Israeli civilians en masse.

But the arrests have netted 15 members of parliament, a football player, a political cartoonist, hundreds of stone-throwing youths and a handful of what Amnesty International calls human rights defenders and prisoners of conscience.

Karajeh, a member of the "Stop the Wall" rights group that campaigns against Israel's vast metal and concrete separation barrier in the West Bank, has yet to be charged.

"We're just confused," said Sundous Mahsiri, his fianc?e and a student at a local university. "Their group doesn't even organise protests, only advocacy work. None of this makes any sense to us."

Seized from his house in the dead of night on Jan. 22, Karajeh has spent the last five weeks in solitary confinement, and complains of being denied medicine for an old leg injury.

According to Israel's military laws in the occupied West Bank, Palestinians can be held for 90 days without charge. In cases that prosecutors believe are especially sensitive, detention can be indefinite.

MASSIVE DEMONSTRATIONS

The latest hearing ended with Karajeh being dispatched back to his interrogators and away again from loved ones, in a pattern that is making Palestinians increasingly furious.

When an apparently healthy, 30-year-old Palestinian died last month after a week in interrogation, massive demonstrations rocked the West Bank.

Palestinian leaders said the man was tortured to death. Israel rejects this, saying cracked ribs and bruises found in an autopsy were likely caused by resuscitation efforts. But it said more tests were needed to determine why the father of two died.

Samer al-Issawi and Ayman Sharawneh, the two hunger strikers at the heart of the recent unrest, were sentenced by Israel to decades behind bars after being convicted of attacking Israeli civilians on behalf of armed groups.

They were released in a prisoner swap in 2011 only to be re-arrested last year and told to serve out their full sentences for fleeing jurisdiction and engaging in unspecified "terror activities".

In coffins or as free men, they have resolved to extract themselves from the legal maze.

Unrest in solidarity with their cause just weeks before U.S. President Barack Obama is due to visit Jerusalem and Ramallah may yet apply pressure on Israel to cut a deal for the release of the duo, while keeping detention policies intact.

Few issues raise as much passion or fury as the question of the prisoners, uniting the fractured Palestinian political landscape unlike any other issue.

"There's no Hamas, no Islamic Jihad and no Fatah when it comes to the sons of the Palestinian people, our heroic prisoners," one activist shouted through a bullhorn at a protest in the West Bank city of Ramallah last week, listing the main factions that are often deeply at odds.

Local authorities estimate that some 800,000 Palestinians have been detained under Israeli military orders since the 1967 war when Israel captured the West Bank, East Jerusalem and Gaza. That represents around 40 percent of the male population and few families have not been directly impacted.

MILITARY TRIBUNALS

The Palestinian Liberation Organisation says those who are charged face a "staggering" 99 percent conviction case in the military tribunals.

"Israel's military courts, in all the versions of their work, exist to facilitate the policies of its occupation," said Jawad Boulos, a veteran lawyer for Palestinian detainees.

But arrests have helped paralyse militant groups that launched attacks on Israeli civilians -- including during the Second Uprising (Intifada) between 2000-2005.

Israel says that in the wake of a brief, bloody war in Gaza at the end of November, it has noted a "marked increase in attempts to execute terrorist attacks against Israeli security forces or civilians" and has stepped up detentions.

"These arrests take place following intelligence indications of terrorist activity," the Israeli military told Reuters.

Palestinian leaders are keen to gain prisoners' freedom to shore up their standing in the eyes of their people, making them useful bargaining chips for Israel.

Islamist group Hamas gained the release of 1,027 prisoners in exchange for Gilad Shalit, an Israeli soldier it abducted in 2006 and held in Gaza for five years.

It was the biggest such exchange carried out by Israel and was widely seen as a triumph for the Palestinian cause.

Palestinian President Mahmoud Abbas, hoping to regain the initiative from his militant rivals in Hamas, has since said he would return to the negotiating table only if more prisoners went free -- especially those incarcerated before the 1993 Oslo Accords that granted the Palestinians limited self-rule.

Israeli government spokesman Mark Regev hinted that more Palestinian detainees might be released in future as a "confidence-building measure", but could give no guarantees about the long-term prisoners sentenced for violence.

"It's a difficult issue given that these people in jail pre-Oslo were sentenced to extended sentences for horrendous crimes," he said.

COLONIAL LEGACY

More than the fate of the 108 "pre-Oslo" prisoners, it is Israel's use of "administrative detention" that remains a main lightning rod of popular anger.

Scores of suspected militants are in jail under the measure, which was adapted from Britain's colonial laws when it governed Palestine, and relies on secret evidence that is presented in closed military courts.

Led by a small group of administrative detainees, a mass Palestinian hunger strike last May was defused by an Egyptian-mediated deal in which prisoners agreed to back off from their protest if Israel curtailed administrative detention.

Since then, the number of Palestinians held without charge has fallen from 308 to 178.

Israel says the practice was sanctioned by international law as a means of pre-empting violence and protecting sources as long as a peace deal with the Palestinians remains elusive.

"We're dealing with hardcore terrorist organisations that have no compunction whatsoever about taking immediate, violent retribution against those testifying in an open court," Regev said.

The May deal did not bring total calm to the prisons, with occasional hunger strikes still rumbling on.

Protesters have for a month held a weekly sit-in outside the Ramallah Red Cross in solidarity with the hunger strikers.

Among dozens of protesters at one rally stood a frail-looking Thaer Halahla, whose 68-day hunger strike gained his freedom from administrative lock-up last year.

Despite having to undergo two operations on his damaged organs, Halahla said hunger striking was a powerful tool against an unjust system.

"It was the most difficult decision a man can take. I did it despite the pain and the threats and pressure from our guards - I felt I was close to martyrdom at any moment," he said.

Last week, Israel struck a deal to free soon two fasting men on administrative detention, leaving just al-Issawi and Sharawneh on the list of long-term hunger strikers.

PROTESTS, PREGNANCIES

In al-Issawiya, Samer's home village, his kinsmen have engaged in rock-throwing clashes with Israeli riot police for much of his six-month fast. A tent set up to hold vigils for him has been taken down by Israeli forces 33 times.

"No matter how many courts he's subjected to, we know that his detention is political and people will keep fighting against it," said his sister, Shireen, a lawyer who has spent a year in Israeli prison.

Palestinians aren't waiting for a diplomatic deus ex machina to try to live a normal life.

A Palestinian fertility centre has offered free insemination treatment to the wives of long-term prisoners, whose sperm they sneak out of Israeli prison and on to the next generation. The campaign has led to one delivery and six pregnancies.

Umm Ali, a woman protesting outside the Red Cross, recalled how she was able to help her son, Refaat Maarif, a prisoner serving a 15-year sentence, get his wife pregnant.

"Prison will not keep our men from having a legacy and passing down their name," Umm Ali said. "The world must realise that the issue of prisoners is the issue of Palestine. If it's not solved, nothing else will be."