An Israeli medical human rights group said today that an increasing number of Palestinian patients from Gaza were being interrogated by Israeli security services before being allowed to leave the strip for treatment.

An Israeli police officer (L) checks identification papers of Palestinians as they wait to cross to Jerusalem at Qalandiya checkpoint near the West Bank city of Ramallah April 27, 2009. (REUTERS/Fadi Arouri) Physicians for Human Rights-Israel said at least 438 patients had been summoned for interrogation by the Shabak, the Israeli general security service, at the Erez crossing out of Gaza between January 2008 and March this year.

It took evidence from several patients and found they were "forced to provide information as a precondition to exit Gaza for medical care". The group said the ratio of applicants being interrogated rose from 1.45% in January last year to 17% in January this year. Their research also suggested the number of interrogations increased sharply from the beginning of this year, after Israel's three-week war in Gaza.

One unnamed patient, who had been referred for orthopaedic treatment to a hospital in east Jerusalem, told the group that as he was trying to leave Gaza he was asked to give information on the people in his neighbourhood and was asked if he knew any Hamas members.

When he refused to give any information, he said his interrogator replied: "I understand that you don't want to answer me and that you don't want to work with us, so go back to Gaza."

Another patient, who was trying to reach a hospital in east Jerusalem, said he was asked: "If you tell me which members of your family belong to the Hamas and which to the Islamic Jihad, I'll let you leave Gaza for the hospital." When he refused, he was told he would be sent back to Gaza.

The group said that patients were photographed by the security services holding a card with their name and identity card number on it, sometimes by coercion.

Others described being insulted during the questioning and being locked up at the crossing, sometimes for several hours without explanation.

Physicians for Human Rights said it took on average six to eight hours for each patient to cross. The group said it believed the Israeli security services were violating international laws on torture and coercion.

"PHR-Israel reiterates its claim that the way in which the GSS [general security service] is exploiting patients' medical conditions by exerting pressure on them, be it overt or hidden, constitutes coercion prohibited under the fourth Geneva convention," it said.

"The exacerbation of the situation is the outcome of failure of public bodies in Israel to take effective steps to restrain the GSS." It was to present its findings to the UN Committee Against Torture in Geneva.

Mark Regev, a spokesman for the Israeli government, rejected the allegations. He said: "The idea that there is a conditionality that people who come into Israel for medical treatment must provide intelligence co-operation is simply untrue."

He said 13,000 Palestinians from Gaza were allowed into Israel last year for medical treatment and said they had to go through "legitimate" security checks.