Sunni Arab leaders and an alleged torture victim gave accounts Wednesday of bloody beatings, starvation and killings in a secret underground prison run by Iraq's Shiite-led Interior Ministry and uncovered by U.S. soldiers.

"Within seconds, I was swimming in the air," said a 20-year-old law student, who asserted in an interview that his captors yanked him to the ceiling by a metal chain looped through cuffs that bound his hands behind his back.

That abuse, he said, began the first torture session in what would be 37 days of confinement. In later sessions, he was placed in a barrel of cold water and simultaneously shocked with electrical current, he said at the headquarters of a Sunni political party, where he spoke on condition of anonymity for fear of retribution by his former captors. His account could not be independently verified.

Three days after U.S. troops entered the illicit prison, and a day after Iraq's Shiite-led government acknowledged the detentions, allegations of torture and long-term detention at the Interior Ministry compound in Baghdad's middle-class Jadriyah neighborhood have become the most prominent of numerous accusations of abuse by the country's Shiite-dominated security forces.

Leaders of Iraq's Sunni Arab minority said Wednesday that beatings at the prison had caused prisoners' broken bones. "Abu Ghraib prison is now considered as heaven compared to Iraqi detention facilities," said Abdul Salam Kubaisi, a senior official of the Association of Muslim Scholars, referring to the U.S.-run prison outside Baghdad where guards abused Iraqi detainees. Several members of the association, a Sunni religious group that includes many hard-line opponents of the U.S.-backed government, were taken to the Interior Ministry prison, Kubaisi said, and at least one disappeared there.

The Interior Ministry compound, which has been the target of repeated car bombings and is surrounded by concrete barricades, is in the heart of Jadriyah. Offices are nearby that house the Supreme Council for the Islamic Revolution in Iraq, a Shiite religious party that is the strongest in Iraq's government and whose Iranian-trained militia fighters now make up a large part of the Interior Ministry's forces.

This summer, the compound became the object of neighborhood rumors of a secret prison and torture center, including talk that it reeked of rotting bodies. Soldiers of the U.S. Army's 3rd Infantry Division entered the compound Sunday night after an Iraqi army commander relayed a report from a Sunni family whose members believed their 14- or 15-year-old son had disappeared inside, the U.S. military said.

The soldiers never found the teenager, but they uncovered an underground bomb shelter that allegedly had been converted into a clandestine torture center where Sunni men appeared to have been held for months, the U.S. military said. Prime Minister Ibrahim Jafari, a member of another Shiite-dominated political party, told reporters Tuesday that 173 men had been found confined there.

The deputy interior minister, Hussain Ali Kamal, told CNN that he had been informed of torturers peeling the skin from detainees. Some of the men, he said, appeared to have been left paralyzed by abuse. An NBC journalist watched as emaciated men were taken from the building over the weekend.

Hadi Amery, head of the Badr Organization, the Shiite militia most often accused of involvement in attacks on Sunnis, denied that the group had anything to do with the prison.

"Badr has nothing to do with this. Why would Badr be involved in the first place?" he told the Reuters news agency. "If there was torture, we ask for an investigation."

The U.S. military gave no immediate details of the alleged abuses but said none of the men required overnight hospital care. An Iraqi official, speaking on condition of anonymity, said the men were taken to a detention center run by Iraq's army.

The senior military commander in Iraq, Gen. George W. Casey Jr., and U.S. Ambassador Zalmay Khalilzad condemned the abuses in a statement Tuesday, and the U.S. military said it would lend logistical and technical support to an investigation promised by Jafari.

Maj. Gen. William Webster, commander of the 3rd Infantry Division, which is responsible for most of Baghdad, said American commanders would go after any other reported secret prisons.

Accounts by jailed Iraqi journalists, international human rights groups and others indicate that beatings and other abuses have been commonplace in detention centers across Iraq. Under Saddam Hussein's Sunni-dominated government, security forces pushed the use of torture to brutal extremes, sending bound prisoners pinwheeling off rooftops, razoring out the tongues of government critics and filming the rapes of women.

Sunni leaders say detentions, torture, assassinations and mass killings now are part of a "dirty war" being waged against their minority group by security forces of the current government, led by members of the Shiite majority.

Many Sunnis accuse Interior Ministry forces and allied Shiite militias of conducting numerous nighttime raids in which scores of Sunni men have been rounded up. The missing men's bodies, handcuffed with gunshot wounds in the head and chest, have been found in groups of 20 or more, sometimes near the Iranian border.

The U.S. military said the Jadriyah center was the first site it had found where captives were subjected to extended confinement and abuse. But Kubaisi, of the Association of Muslim Scholars, said other secret prisons in Baghdad held thousands of Sunnis. He refused to pinpoint them, saying he feared security forces would kill detainees to remove evidence of wrongdoing.

Sunnis at the Jadriyah facility had been whipped with cables and beaten until they lost control of their bladders, among other abuses, Kubaisi said.

Kubaisi and other Sunni leaders rejected the idea that Jafari's administration had not known of the secret prison, saying they had told Jafari and other top Shiite politicians repeatedly.

"We've been calling for a long time, but no one listened to us," Kubaisi said.

The 20-year-old student said his own ordeal began Sept. 3, when armed men in the camouflage uniforms and vehicles of Interior Ministry commandos stopped at his house. An apparent civilian with the commandos, his face covered by a ski mask, pointed out the 20-year-old and his 23-year-old brother, for reasons the brothers never learned, he said.

The brothers were blindfolded and taken to "a freezing-cold building," the 20-year-old said. "We heard people screaming of torture. We heard sounds of sticks beating bodies and drills working, but never knew what that was."

Men called the brothers and other detainees "Sunni dogs" and "suicide-bombers to be," he said.

Subsequent torture sessions left the third-year law student screaming and begging as his captors suspended him by his contorted arms, beat him with sticks and electrical cables and subjected him to electric shocks.

"Confess," an investigator ordered at one point, then ticked off recent car bombings in Baghdad, the 20-year-old said. "He asked me to choose one of them to confess that I perpetrated. It was like in a restaurant and he was asking me what I would like to eat."

Part of his stay was spent with about 80 men, young and old, most in shirts filthy with dried blood from torture, he said. Guards gave the Sunnis only three pieces of bread a day and sips of water from a bottle cap, he said.

"We wished to be transferred to Bucca or Abu Ghraib," he said. "At least the Americans won't treat us like this."

The brothers were released after more than a month, still without explanation, he said. "We couldn't believe it. I thought they meant we were going to be killed."

The 20-year-old, now healthy-looking in a sweater and tracksuit pants, said he bore no scars from the abuse.

Sunni leaders offered no other immediate evidence of any abuse, though Kubaisi said they had CDs, documents and other files detailing the detentions.

Lt. Col. Steve Boylan, a U.S. military spokesman, said any photographs, documents or other evidence gathered by the Americans would be kept private pending investigations.

Special correspondents Bassam Sebti and K.I. Ibrahim and correspondent Jonathan Finer contributed to this report.

An Iraqi policeman shows bruises as he is treated at Yarmouk Hospital in Baghdad. Four policemen said they had been beaten after being stopped Monday by men who identified themselves as Interior Ministry commandos. Tariq Hashimi, secretary general of the Iraqi Islamic Party, a Sunni group, displays pictures of prisoners allegedly tortured by Iraqi security forces. Hashimi and others also called for an international investigation into the allegations.