A Palestinian man detained by Israel and on hunger strike for 41 days is in danger after beginning to refuse liquids, a rights group said on Tuesday, demanding he be transferred to a civilian hospital.

Tel Aviv-based Physicians for Human Rights-Israel said the condition of Bilal Diab, who has refused food since March 1, was "very worrisome," particularly after he began refusing liquids on Sunday.

Following a court petition, a physician for the organisation was permitted on Monday to visit Diab, a 27-year-old from an area near Jenin, in the northern West Bank.

The group was also able to visit Thaer Halahla, a 34-year-old from Hebron, who has also been on hunger strike since March 1 but is still accepting fluids. Both men are hospitalised in a prison facility near Tel Aviv, the group said.

A PHR doctor said Halahla´s condition was "in accordance with a long hunger strike, yet stable," but warned of a deterioration in his health if he continued the protest.

The group said Diab had told the PHR doctor he would reconsider refusing fluids if he were moved to a civilian hospital.

The group urged Israel to make such a transfer immediately, and to enable independent physicians to regularly examine detainees on hunger strikes without the presence of a prison doctor, and with family members in attendance.

Israel Prison Service spokeswoman Sivan Weizman told AFP "detainees on hunger strikes are receiving care and are under the necessary medical supervision."

According to the Palestinian Prisoners´ Club, which tracks detainees in Israeli jails, Diab and Halahla are both being held under administrative detention orders.

These orders allow a court to order an individual to be detained without charge for periods of up to six months at a time, which can then be extended.

PHR said Halahla has been in detention since June 2010, and Diab since August 2011. The men are allegedly associated with Islamic Jihad, but they have not been prosecuted.

According to PHR and the Palestinian Prisoners´ Club, Halahla and Diab began their hunger strikes after their detention orders were renewed, as part of the wave of protest among administrative detainees sparked by Palestinian prisoners Khader Adnan and Hanaa Shalabi.

Adnan, who launched a high-profile 66-day hunger strike, agreed to end it in February after striking a deal with Israel to be released at the end of his current detention period.

Shalabi was deported to Gaza earlier this month, after a hunger strike of 43 days.

There were approximately 300 Palestinians being held in Israeli prisons under administrative detention as of February, according to the Israel Prison Service.

Weizman told AFP that besides Halahla and Diab there are another five Palestinian detainees on hunger strike in Israeli prisons. The Palestinian Prisoners Club puts the figure at eight. (Copyright © 2012 Agence France Presse. 04/10/12)