As many as 2,000 Palestinian prisoners – nearly half of the 4,500 Palestinians currently in Israeli jails – have launched a mass hunger strike that is gaining momentum and putting pressure on Israel to review prisoner demands.

More prisoners join each day, and many see hunger striking as their last option, especially those who are held without charge or trial under Israel's administrative detention policy and limited legal recourse. They blame not only the Jewish state, which defends the policy as necessary to its security, but also the Palestinian Authority for not securing better rights for prisoners.

“The hunger strike is the strongest thing the detainee can do … a person inside jail can’t make any other kind of resistance,” says Khader Adnan, a member of the Islamic Jihad militant movement whose 66-day hunger strike earlier this year became something of a cause célèbre among Palestinians. “Because the detainee has no instrument for protesting, to make his voice loud, except this kind of protest. A hunger strike is using the man’s own body as an instrument against humiliation and oppression.”

Among those who followed Mr. Adnan's example are the two longest hunger strikers are Bilal Diab and Thaer Halahleh, who have refused food for 66 days and are in critical condition, according to Physicians for Human Rights-Israel.

Robert Serry, the United Nations envoy for Middle East peace, issued a statement yesterday saying he was "deeply troubled" by the conditions of those prisoners, who are being held in administrative detention. "Above all, he urges all sides to find a solution before it is too late, and calls on Israel to abide by its legal obligations under international law and do everything in its power to preserve the health of the prisoners," the statement said.

Since Israel occupied the West Bank and Gaza in 1967, Palestinian prisoners have executed more than a dozen hunger strikes. One in five Palestinians has spent time in an Israeli jail, according to prisoner support group Adameer, and almost every family has had a member incarcerated.

But Israel, which has lost thousands of civilians to Palestinian terrorist attacks, says it is not locking up just anyone.

“These are not boy scouts,” says the Israeli prime minister's spokesperson, Mark Regev, cautioning that most prisoners refusing food have been convicted of crimes by Israel. Mr. Adnan, he points out, is an admitted member of Islamic Jihad – an organization that has claimed responsibility for the deaths of scores of Israelis. He calls the use of administrative detention “unfortunate, but necessary” because it is used to protect informants who provide information about those being detained.

Of those in Israeli jails, at least 300 are being held under administrative detention orders, which can be repeatedly renewed without a transparent judicial process. In a report released May 2, Human Rights Watch said, “Israel should immediately charge or release people jailed without charge or trial under so-called administrative detention."

“Administrative detention is not meant to be used as a substitution for a criminal process,” says Sarit Michaeli, a spokesperson for the Israeli human rights organization, B'Tselem. “All the evidence is secret. It removes the ability of a person to defend themselves.”

Palestinian, Israeli, and international activists have been holding regular protests in a show of solidarity with Palestinian prisoners. Yesterday protesters clashed with the Israeli army outside Israel’s Ofer military prison near the city of Ramallah in the West Bank. Youth armed with slingshots, their faces covered with keffiyehs, pelted soldiers with rocks outside the prison where Israel holds around 500 Palestinian detainees.

“I want the prisoners to take their rights. To have their demands met. I want to show them we are here with them,” says one young female activist, her identity concealed by a scarf wrapped around her face and large sunglasses in the midst of a barrage of tear gas used by the army to push back the demonstrators on Thursday. “[The Palestinian Authority] is not doing enough. By hunger striking, Khader Adnan took what he wanted.”

Indeed, Mr. Adnan is a new symbol of resistance in the Palestinian Territories. He was arrested in his home on Dec. 17, 2011. Although he is a member of the Islamic Jihad organization, considered a terrorist group by Israel and the US, he was not charged with any crime.

He was held under administrative detention based on secret evidence, and even he didn’t know the details of the accusations against him. He started his hunger strike to protest his nine arrests over the last 12 years, abusive treatment by Israeli forces, and detention without charge. For 66 days he refused food before an agreement was reached to release him.

A stencil of Mr. Adnan’s face with a padlock pressed between his lips began appearing on walls and placards across the West Bank. Spaces once filled with martyr posters of young men with multiple weapons now feature his bearded face with thin-rimmed glasses, popularizing the nonviolent hunger-strike tactic and drawing attention to his case.

Sivan Weizman, a spokesperson for the Israeli Prison Service, says they have created a team to review the requests of the prisoners, which include an end to this practice of administrative detention and isolation, as well as lifting recent restrictions on family visits and access to university education.

But they are not bowing to the prisoners’ demands because of this wide-scale action, she says, noting that the team was assembled before the mass hunger strike started. “Let’s be clear,” Ms. Weizman says, “It’s not because of the strike.”

As of yet, the mass hunger strike has produced no concrete results and rights groups say the Israeli authorities are punishing those who refuse to eat by removing electronics from their rooms and further restricting contact with their families and other prisoners. Weizman says some prisoners have been moved and had “privileges” taken away, but says it’s not “punishment.”

Sahar Francis, a lawyer and director from the prisoner support group Adameer, calls Adnan’s case a victory and says that reviewing Israel’s reaction so far to the mass hunger strike shows Israel sees the tactic as a threat. “It puts pressure on the prison system,” says Ms. Francis.