Majdi Jabour was beaten to the point of passing out by the Fatah-allied interrogators in the West Bank who accused him of ties to rival Hamas. In Gaza, the same fate befell a Fatah supporter who was bloodied in a lockup by club-wielding Hamas security men.

Two human rights groups on Monday decried widespread mistreatment and torture in Palestinian jails — an issue taking on fresh urgency with a new round of mass arrests over the weekend in both in Hamas-run Gaza and in the Fatah-controlled West Bank.

In conversations with The Associated Press, three detainees gave similar accounts and a doctor confirmed Jabour had been badly beaten.

The Palestinian group Al Haq and the U.S.-based Human Rights Watch looked at human rights violations during the past year, since the Islamic militant Hamas wrested control of Gaza from the forces of Palestinian President Mahmoud Abbas of Fatah.

In the past year, the security forces in both the West Bank and Gaza have carried out large-scale, arbitrary arrests of political opponents, the Palestinian human rights group Al Haq said in an 85-page report.

More than 1,000 people were detained by each side, Al Haq estimated, even before a roundup of some 200 Fatah supporters in Gaza over the weekend, following a bombing that killed five Hamas activists. On Monday, Abbas' forces in the West Bank rounded up dozens of Hamas supporters in apparent retaliation for the Gaza sweep.

An estimated 20 to 30 percent of the detainees suffered torture, including severe beatings and being tied up in painful positions, said Al Haq director Shawan Jabarin, citing sworn statements from 150 detainees. He said three died in detention in Gaza and one in the West Bank.

"The use of torture is dramatically up," added Fred Abrahams, a senior researcher for Human Rights Watch, a U.S.-based group that is releasing its own report on abuse later this week.

Jabarin, the Al Haq director, said that while he had no proof of an official torture policy, he believed that political leaders were indirectly encouraging abuse by looking the other way.

Abbas' Prime Minister, Salam Fayyad, acknowledged "shortcomings," but said human rights violations have decreased. "I'm not defending anyone, but I can assure you that we have treated flaws and don't allow violations. The upcoming reports will be better," Fayyad said.

In Gaza, Hamas spokesman Fawzi Barhoum accused the Fayyad government of trying to destroy Hamas in the West Bank with U.S. backing. Barhoum acknowledged "mistakes" were made by the Hamas forces, but said that unlike in the West Bank, violators were increasingly punished.

Human Rights Watch also said that Abbas' forces need to come under closer scrutiny because of the massive international support they enjoy. Funding of Abbas' forces should be linked to an improvement in the human rights record, Human Rights Watch said.

"The international community has pledged $8 billion to the Palestinian Authority in the West Bank and that gives them a heavy responsibility to make sure the security forces don't use torture and respect human rights," said Abrahams.

Two branches of the Palestinian security, the national forces and the civil police, receive training from the U.S. and Europe, respectively. Neither force was cited in the Al Haq report as being involved in abuse.

The office of Washington's security envoy in the Palestinian areas, Lt. Gen. Keith Dayton, declined comment on the Al Haq allegations, but noted that human rights training is part of the curriculum.

Colin Smith, who leads the European effort, added that "the Palestinians themselves are looking to restructure the security force into a more accountable, transparent force."

The Al Haq report described a series of methods used by interrogators in both territories. Commonly, detainees' heads were covered by sacks and their hands tied behind their backs. They were made to stand for long hours. Those who moved risked beatings on arms, legs and the soles of feet. Other methods included threats, humiliation and isolation in tiny cells.

Three ex-detainees — two from the West Bank village of Salem and one from Gaza — gave similar accounts to AP.

Jabour, a 33-year-old construction worker, said he was detained on Nov. 17 by Military Intelligence in the city of Nablus, near Salem. He said interrogators demanded to know where he had hidden the automatic rifle of his late brother, a member of the Hamas military wing killed by Israel in 2002.

Jabour said he insisted he had no ties to Hamas and did not know of a weapon.

He said that for the next six days, he was beaten severely with sticks and fists, including on the soles of his feet. His legs became so swollen and his feet so sore that he couldn't stand up, he said. He also was forced to kneel on glasses placed upside down on the floor and made to stand in the cold winter rain for hours.

Jabour said he was taken to Nablus' Rafidiyeh Hospital after an interrogator rammed a screwdriver into his back, making him pass out.

Dr. Marwan Jayousi, who examined Jabour at the hospital, told the AP that the patient's legs were heavily bruised and very swollen at the time.

"There were a lot of marks of beatings by sticks, on his back, on his scapula, shoulders, and it was painful," the physician said.

Jayousi said he prescribed painkillers and antibiotics, and that the men in uniform took Jabour away. Jabour said he was transferred to the General Intelligence Service in Nablus, where the abuse largely stopped.

Several days later, he returned to the Nablus hospital, where he underwent an operation for what Jayousi said fellow doctors told him was a perforated appendix.

After recovering from the operation, he was released without charges. Jabour, whose leg bruises are still visible eight months after his release, said the Nablus governor apologized to him.

Another man from Jabour's village, 50-year-old Hosni Jabara, said he was arrested by the Preventive Security Service in Nablus on Jan. 28, and was tied up in painful positions off and on for 32 days.

At times, he was pulled off the ground by a rope hanging from the ceiling and attached to his hands tied behind his back, Jabara said. He said he told his interrogators he's a proud member of Hamas, but that he has no knowledge of weapons, and he eventually was released.

In Gaza, a Fatah supporter said he was seized by Hamas security and beaten severely for several hours this spring, until he lost consciousness and had blood streaming down his face. After initially agreeing to be quoted and photographed, he withdrew permission, saying he had received new threats from Hamas.