JERUSALEM - Israeli interrogators often beat Palestinian suspects, shackle them in painful positions and disrupt their sleep, defying a 1999 court ruling outlawing torture, two Israeli rights groups said yesterday.

One Palestinian said his captors made him arch his back over a bench with his hands and legs joined in what prisoners commonly call "the banana position," concluded a report by B'Tselem and the Center for the Defense of the Individual.

"They brought a chain and used it to hook together the handcuffs and leg shackles. The way this made my body stretch was unbearable," said the man, identified as A.Z., 29. "Then the interrogators lifted the bench from both ends and dropped it suddenly. At that point I lost consciousness."

Israel's Supreme Court in 1999 outlawed what the Shin Bet security service called "moderate physical pressure," such as sleep deprivation, exposure to extreme temperatures, and tying up detainees in painful positions.

Israel's Justice Ministry said interrogations were carried out within the law and called the report badly flawed. It said Shin Bet interrogations were part of Israel's "day by day fight against terrorists" and many civilian lives had been saved by information gained from its investigations.

The report was based on affidavits from 73 Palestinians detained between July 2005 and January 2006. Most testimony was taken by a rights groups' lawyer who visited detainees in their cells, the report said.

Prisoners said they were physically abused, humiliated, sworn at, threatened, deprived of sleep and routinely held in appalling conditions, including isolation, the report said.

"Their purpose is to break the interrogees' spirit and as such, they contradict the Supreme Court ruling and constitute prohibited ill-treatment under international law," the report said.

No criminal investigations have been opened against Shin Bet interrogators; 500 complaints have been filed since 2001, B'Tselem research director Yehezkel Lein, the report's author, said.

Israel's Justice Ministry, which received a copy of the report, said that Shin Bet interrogations are "performed in accordance with the law."

Hundreds of Israelis have died in suicide bombings, shootings and other Palestinian attacks since the outbreak of the Palestinian uprising in October 2000. Israeli defense officials say the death toll would be many times higher but the vast majority of attempts are thwarted, often by Shin Bet warnings.

Lein admitted the security concern but said that it was not a defense under international law and that those involved could be liable to prosecution if they visited other countries.