RAMALLAH, West Bank (Reuters) - Hundreds of Palestinian prisoners in Israeli jails declared a one-day fast on Tuesday in solidarity with four inmates whose hunger strike has fuelled anti-Israel protests in the occupied West Bank.

A Palestinian throws a rock towards an Israeli police vehicle during clashes outside Israel's Ofer military prison near the West Bank city of Ramallah February 19, 2013. Hundreds of Palestinian prisoners in Israeli jails declared a one-day fast on Tuesday in solidarity with four inmates whose hunger strike has fuelled anti-Israeli protests in the occupied West Bank. REUTERS/Mohamad Torokman

Samer al-Issawi, one of the four Palestinians who have been on hunger strike, has been refusing food, intermittently, for more than 200 days. His family says his health has deteriorated sharply.

The prisoners' campaign for better conditions and against detention without trial has touched off violent protests over the past several weeks outside an Israeli military prison and in West Bank towns.

In the Gaza Strip, the Islamic Jihad group said a truce with Israel that ended eight days of fighting in November could unravel if any hunger striker died.

The Palestinian Prisoners Club, which looks after the welfare of inmates and their families, said 800 prisoners were taking part in the day-long fast.

Issawi was among 1,027 jailed Palestinians freed by Israel in 2011 in exchange for Gilad Shalit, a soldier who was abducted on the Gaza border by Hamas, the Islamist militant group that now rules the enclave.

Issawi and Ayman Sharawneh, who has also been on hunger strike, are among 14 Palestinians who have been re-arrested by Israel since being released in the Shalit trade.

Ofir Gendelman, a spokesman for Israeli Prime Minister Benjamin Netanyahu, wrote on Twitter that Issawi and Sharawneh were detained "because they violated the terms of the Shalit deal by returning to illegal activities which pose a threat".

INTERNATIONAL CONCERN

Palestinian negotiator Saeb Erekat said he had been in contact with Israel and urged it to release the men. He said Egypt, which helped mediate the Shalit prisoner swap and also negotiated an end to a Palestinian mass hunger strike in Israeli jails last year, was trying to end the new protest.

Israel has defused previous long-term hunger strikes among the some 4,700 Palestinians in its jails by agreeing to release individuals or deporting them to Gaza - a prospect rejected by the four protesters, who hail from Jerusalem and the West Bank.

The Quartet of Middle East negotiators - the United States, Russia, the United Nations and European Union - have expressed concern at the hunger strike.

In a statement on Monday, France's Foreign Ministry urged Israel "to be sensitive to the risk of a tragic outcome and to take appropriate measures as a matter of urgency".

The statement said "administrative detention must remain an exceptional measure of limited duration and be carried out with due regard for fundamental safeguards".

Israel holds some Palestinians in "administrative detention" based on evidence presented in a closed military court. It says the practice pre-empts militant attacks against it while keeping its counter-intelligence sources and tactics secret.

There were some 178 administrative detainees in Israeli jails in January, down from a high of just over 300 around the time of another Palestinian hunger strike campaign last spring, according to Palestinian rights group Addameer.

"The battle waged by me and by my heroic colleagues ... is everyone's battle, the battle of the Palestinian people against the occupation and its prisons," Issawi said in a message conveyed to the Palestinian Ministry of Prisoners last week.

(Additional reporting by Nidal al-Mughrabi in Gaza and Ali Sawafta in Ramallah; Editing by Alison Williams)

• Malaysia's blue chips fall more than 6pts in early trade
• Profit taking may weigh on Malaysian equities
• HP raises 2013 outlook as Whitman's plan takes hold
• Bernanke says more progress needed before stimulus pullback
• Wall Street falters in volatile session on Fed worries
• Aeon director: GST won’t affect group
• Petronas Chemicals Group to invest RM3bil in capital expenditure
• Weak CPO prices hit Boustead profit
• April CPI up 1.7% on higher food prices
• Report: AirAsia X sets indicative price for IPO
• MAEI sees 3%-4% rise in electrical, electronics exports
• Cahaya Mata Sarawak to invest in grinding plant
• Star to leverage on new, fast-growing businesses
• No plans for MBO, says Vincent Lee
• Axiata said to weigh bid for Axis Telekom Indonesia

• Anti-Islamist protests flare following London attack
• 'British solider' butchered in suspected Islamist attack

• Ice queen Nicol into British Open quarters
• Australia to consider following ban on anchor putters
• Intxausti wins 16th stage, Nibali still keeps pink jersey
• Indonesia drawn to meet China again – in knockout stage
• Results worldwide
• Malacca sprinter Mohd Azam Masri out to create history by winning five events in MSSM meet
• Athletics runs in the veins of Vallabouy family
• Chinese long jumper Jinzhe claims another Olympic scalp
• Dane Jorgensen’s wish is to avoid Chinese ace Lin Dan in World Championships
• National badminton team’s lack of depth a glaring factor in home tourney
• Khim Wah-V Shem perform above expectations in Sudirman Cup debut
• Jindapon aims to qualify for 2016 Olympics
• Kenichi’s goal is to take Japan into Sudirman Cup semi-finals
• Dong-keun shows he’s a capable replacement
• Harrison makes swift U-turn

• Please wait.

• What comes after WYY?
• Actress’ barking pet saves her from attacker in late night incident
• Chromebook to help rural pupils leapfrog into parity with urban peers
• Asean flavour in Invest M’sia confab
• We have to be humane to all who are put under arrest
• We must look at language as an asset
• Prime Minister to address global women conference
• Petronas Chemicals Group to invest RM3bil in capital expenditure
• Report: AirAsia X sets indicative price for IPO
• Lower net profit for AirAsia