The UN is demanding that Facility 1391, a secret prison camp in northern Israel where it is believed prisoners are routinely tortured, be opened to inspectors.

Nazareth, Israel // The United Nation’s watchdog on torture has criticised Israel for refusing to allow inspections at a secret prison, dubbed by critics as “Israel’s Guantanamo Bay”, and demanded to know if more such clandestine detention camps are operating.

In a report published on Friday, the Committee Against Torture requested that Israel identify the location of the camp, officially referred to as “Facility 1391”, and allow access to the International Committee of the Red Cross.

Findings from Israeli human rights groups show that the prison has in the past been used to hold Arab and Muslim prisoners, including Palestinians, and that routine torture and physical abuse were carried out by interrogators.

The UN committee’s panel of 10 independent experts also found credible the submissions from Israeli groups that Palestinian detainees were systematically tortured despite the banning of such practices by the Israeli Supreme Court in 1999.

The existence of Facility 1391 came to light in 2002, when Palestinians were detained there for the first time during Israel’s reinvasion of the West Bank.

In a submission to human rights groups last week, Israel denied that any prisoners are currently being held at the site, although it admits that several Lebanese were detained there during the attack on Lebanon in 2006. The committee expressed concern about an Israeli Supreme Court ruling in 2005 that found it “reasonable” for the state not to investigate suspicions of torture at the prison. The panel is believed to be concerned that without inspections the prison might still be in use or could be revived at short notice.

The Israeli court, the committee wrote, “should ensure that all allegations of torture and ill-treatment by detainees in Facility 1391 be impartially investigated [and] the results made public”.

Hamoked, an Israeli human rights organisation, first identified the prison after two Palestinian cousins seized in Nablus in 2002 could not be traced by their families. Israeli officials eventually admitted that the pair were being held at a secret site.

Israel still refuses to identify the precise location of the prison, which is inside Israel and about 100km north of Jerusalem. A few buildings are visible, but most of the prison is built underground.

“We only learnt about the prison because the army made the mistake of putting Palestinians there when they ran out of room in Israel’s main prisons,” said Dalia Kerstein, the director of Hamoked.

“The real purpose of the camp is to interrogate prisoners from the Arab and Muslim world, who would be difficult to trace because their families are unlikely to contact Israeli organisations for help.”

Ms Kerstein said the prison site was an even grosser violation of international law than Guantanamo Bay because it had never been inspected and no one knew what took place there.

According to the testimonies of the Palestinian cousins, Mohammed and Bashar Jadallah, they were held in isolation cells measuring two metres square, with black walls, no windows and a light bulb on 24 hours a day. On the rare occasions they were escorted outside, they had to wear blacked-out goggles.

When Bashar Jadallah, 50, asked where he was, he was told he was “on the moon”.

According to the testimony of Mohammed Jadallah, 23, he was repeatedly beaten, his shackles tightened, he was tied in painful positions to a chair, he was not allowed to go to the toilet and he was prevented from sleeping, with water thrown on him if he nodded off. Interrogators are also reported to have shown him pictures of family members and threatened to harm them.

Although Palestinians passing through the prison were interrogated by the domestic secret police, the Shin Bet, foreign nationals at the prison fall under the responsibility of a special wing of military intelligence known as Unit 504, whose interrogation methods are believed to be much harsher.

Shortly after the prison came to light, a former inmate – Mustafa Dirani, a leader of the Lebanese Shia group Amal – launched a court case in Israel claiming he had been raped by a guard.

Mr Dirani, seized from Lebanon in 1994, was held in Facility 1391 for eight years along with a Hizbollah leader, Sheikh Abdel Karim Obeid. Israel hoped to extract information from the pair in its search for a missing airman, Ron Arad, downed over Lebanon in 1986.

Mr Dirani alleged in court that he had been physically abused by a senior army interrogator known as “Major George”, including an incident when he was sodomised with a baton.

The case was dropped in early 2004 when Mr Dirani was released in a prisoner exchange.

Ms Kerstein said there was no proof that more prisons existed in Israel like Facility 1391, but some of the testimonies collected from former inmates suggested that they had been held at different secret locations.

She said the concern was that Israel might have been one of the countries that received “extraordinary rendition” flights, in which prisoners captured by the United States were smuggled to other countries for torture.

“If a democracy allows one of these prisons, who is to say that there are not more?” she said.

The committee examined other suspicions of torture involving Israel. It expressed particular concern about Israel’s failure to investigate more than 600 complaints made by detainees against the Shin Bet since the panel’s last hearings, in 2001.

It also highlighted the pressure put on Gazans who needed to enter Israel for medical treatment to turn informer.

Ishai Menuchin, executive director of Israel’s Public Committee against Torture, said his group had sent several submissions to the committee showing that torture was systematically used against detainees.

“After the court decision in 1999, interrogators simply learnt to be more creative in their techniques,” he said.

He added that, since Israel’s redefinition of Gaza as an “enemy state”, some Palestinians seized there were being held as “illegal combatants” rather than “security detainees”.

“In those circumstances, they might qualify for incarceration in secret prisons like Facility 1391.”