American defense officials confirmed last week that U.S. forces have interrogated some detainees in Yemen but denied any participation in or knowledge of human rights abuses. The American officials confirmed that the U.S. provides questions to the Emiratis and receives transcripts of their interrogations. A Yemeni witness of American interrogations also told the AP that no torture took place during those sessions where he was present.

Still, the American role raises concerns about violations of international law. Obtaining intelligence that may have been extracted by torture inflicted by another party would violate the International Convention Against Torture, which prohibits complicity, said Ryan Goodman, a law professor at New York University who served as special counsel to the Defense Department until last year.

Pressure mounted on the Defense Department on Friday after multiple U.S. senators called for investigations into reports that U.S. military interrogators worked with forces from the UAE who are accused of torturing detainees in Yemen.

John McCain, Republican chairman of the Senate Armed Services Committee, and the ranking Democrat, Jack Reed, called the AP reports “deeply disturbing.”

McCain and Reed said they have written a letter to Defense Secretary Jim Mattis asking him to conduct a review of the reported abuse and what U.S. forces knew.

‘Little Sparta’

Washington has long relied on allies to help it gain intelligence in the fight against al-Qaida. The UAE has been so key that Mattis praised it as “Little Sparta” for its outsized role in fighting the militants. The UAE government in a statement to the AP denied that any secret prisons exist or that torture takes place.

At one main detention complex at Riyan airport in the southern Yemeni city of Mukalla, however, former inmates described being crammed into shipping containers smeared with feces and blindfolded for weeks on end. They said they were beaten, rotated on a spit and sexually assaulted, among other abuse. Speaking on condition of anonymity, one member of the Hadramawt Elite, a Yemeni security force set up by the UAE, said American forces were at times only yards away.

“We could hear the screams,” said a former detainee held for six months at Riyan. “The entire place is gripped by fear. Almost everyone is sick, the rest are near death. Anyone who complains heads directly to the torture chamber.”

He was flogged with wires, part of the frequent beatings inflicted by guards against all the detainees, the AP found. He also said he was inside a metal shipping container when the guards lit a fire underneath to fill it with smoke.

One fellow inmate tried to slit his own throat; another tried to hang himself, he said. t

He and the other former detainees spoke on condition of anonymity for fear of being arrested again. They said that when they were released, Emirati officers forced them to sign a document not to talk publicly about what they had endured.

“When I left the container, it was like escaping death,” he said.

Lawyers and families estimate nearly 2,000 men have disappeared into the system. The AP interviewed 10 former prisoners, as well as a dozen officials in the Yemeni government, military and security services and nearly 20 relatives of detainees.

Ali Awad Habib, a businessman who was detained in the city of Aden, described how he was given electrical shocks on his neck, back, chin and “sensitive parts” of his body, after being imprisoned by the Security Belt, another Yemeni force created by the UAE.

His father, arrested with him in April 2016, was sent to an Emirati base across the Red Sea in the Horn of Africa nation of Eritrea. Yemeni Interior Minister Hussein Arab confirmed that a number of detainees have been sent to the base in the port of Assab.

Chief Pentagon spokeswoman Dana White said the Defense Department has “found no credible evidence to substantiate that the U.S. is participating in any abuse.”

“We always adhere to the highest standards of personal and professional conduct,” she said when presented with AP’s findings.

However, several U.S. defense officials said senior military leaders are aware of the allegations of torture at the prisons in Yemen and have looked into them. In the end, they were satisfied that there has not been any abuse when U.S. forces are present, the officials said. They weren’t authorized to speak publicly on military operations and requested anonymity.

The officials said members of the Pentagon’s Joint Special Operations Command or other military intelligence experts participate in interrogations of detainees at locations in Yemen. They said JSOC troops are trained to look for signs of abuses and are required to report it.

The network of Emirati prisons echoes the so-called “black sites,” secret detention facilities set up by the CIA to interrogate terrorism suspects in the aftermath of the 9/11 attacks. In 2009, then-President Barack Obama disbanded the sites. The UAE network in war-torn Yemen was set up during the Obama administration and continues operating.

Laura Pitter, senior national security counsel at Human Rights Watch, said the abuses allegedly committed by the UAE “show that the U.S. hasn’t learned the lesson that cooperating with forces that are torturing detainees and ripping families apart is not an effective way to fight extremist groups.” Human Rights Watch issued a report last week documenting torture and forced disappearances at the UAE-run prisons and calling on the Emirates to protect detainees’ rights.

Amnesty International called for a U.N.-led investigation into allegations the U.S. interrogated detainees or received information possibly obtained from torture.

“It would be a stretch to believe the U.S. did not know or could not have known that there was a real risk of torture,” said Amnesty’s director of research in the Middle East, Lynn Maalouf.

The UAE is part of a Saudi-led, U.S.-backed coalition fighting in support of Yemen’s government against Shiite rebels known as Houthis, who overran the north of the country. The 2-year-old civil war has pushed the already impoverished nation into near famine in some areas.

The coalition is also fighting al-Qaida’s branch in the Arabian Peninsula, as well as Islamic State militants in Yemen. The Pentagon has said it sent a small contingent of U.S. forces in Mukalla last year, in an intelligence sharing role, and that forces move in and out routinely.

Under the Trump administration, the U.S. has escalated drone strikes to more than 80 this year, up from 21 in 2016, according to U.S. Central Command.

At the same time, the UAE has carved out its own state-within-a-state in southern Yemen. It has set up an extensive security apparatus, created its own Yemeni militias and runs military bases. The result has undermined the internationally recognized government of President Abed Rabbo Mansour Hadi. UAE-trained and financed forces like the Hadramawt Elite and Security Belt are under Hadi’s government, but Hadi’s officials often complain that those forces answer only to the Emiratis.

“There are no secret detention centers and no torture of prisoners is done during interrogations,” the UAE government said.

It said all prisons are administered by Yemeni security forces under the Hadi’s government.

But multiple former detainees who described months of torments in black sites where they had no hope of being found said their biggest terror was the Emirati interrogators — like the one known only as “the Doctor.”

Grilled on a spit

The guards would bang on the metal doors of the shipping containers, shouting that “the Doctor” had arrived. The prisoners inside, blindfolded and bound, didn’t know his real name: They knew only his Emirati accent as he asked questions and inflicted pain.

One of his torments was to hang weights on an inmate’s genitals and pull. Another former detainee described being put on “the grill”: Blindfolded, he was tied to a horizontal pole inside a circle of flame. He said he was spun so fast that he vomited blood.

All six former inmates from Riyan, each interviewed separately by the AP, said they were beaten with wires, often by the Doctor.

One detainee told of undergoing a fake execution where he was dressed in what he was told was an explosive suicide belt, then a sound grenade was set off near him.

Riyan was once Mukalla’s commercial airport but has been turned into a coalition base.

There, detainees were initially crammed by the dozens into a hangar and into 10-by-33-feet shipping containers, according to the six former inmates. The detainees were kept blindfolded, their legs and hands bound for months on end.

“Imagine having your eyes covered for 100 days, you feel like you’re the walking dead,” said the ex-inmate who was there for six months. He was allowed to care for his fellow detainees and came to know many.

Diarrhea was rife because of unclean water; access to toilets was limited, and the containers reeked, he said. Emirati officers would hold their noses from the stench, he and other detainees said. Emirati officers interrogated the detainees at Riyan, while members of the Hadramawt Elite served as guards.

Mukalla, the capital of Hadramawt province, is a major focus in the fight against al-Qaida by the UAE and the Hadramawt Elite.

Overlooking the Arabian Sea, the city was overrun by al-Qaida in 2015. Militants dominated the city for around a year until they fled before a planned assault by the Hadramawt Elite.

The ships

Several inmates said guards frequently threatened prisoners by saying they would “take them to the ships.”

Senior U.S. defense officials flatly denied the U.S. military conducts any interrogations of Yemenis on any ships.

“We have no comment on these specific claims,” said Jonathan Liu, a CIA spokesman, adding that any allegations of abuse are taken seriously.

But a Yemeni officer told AP he had worked on a vessel off the coast where he saw at least two detainees brought for questioning.

He said the detainees were taken below deck, where he was told American “polygraph experts” and “psychological experts” conducted interrogations. He did not have access to the lower decks and thus had no first-hand information about what happened there.

But he said he saw other Americans in uniforms on the ship. The officer spoke on condition of anonymity because he feared retaliation for discussing the operations.

A second Yemeni officer said he was involved in moving detainees to a ship, where he said he saw foreigners though he didn’t know their nationality.

“They say these are the important ones. Why are they important? I have no idea,” he said of the detainees.

A top official in Hadi’s Interior Ministry and a senior military official in the 1st Military District, based in Hadramawt, also said that Americans were conducting interrogations at sea, as did a former senior security official in Hadramawt. The three men spoke to the AP on condition of anonymity because they were not authorized to share military information.

The accusations of an American role raises the prospect of potential violations of U.S. and international law. Article 4 of the U.N. Convention against Torture bans any act that “constitutes complicity” in torture.

In the aftermath of publicized abuses of prisoners by American soldiers at Abu Ghraib in Iraq, and the use of waterboarding, then-president Obama shut down the “black site” prisons used by the CIA in 2009 and outlawed the use of torture during interrogations of anyone “in the custody or under the effective control of” the U.S.

Trump has voiced his belief that torture works, and his administration initially indicated it could review Obama’s black site ban, but it has not done so.

“The U.S. has a positive obligation under international law to prevent torture instead of acquiescing in it,” said Amrit Singh, a senior legal officer at the Open Society Justice Initiative. “It would therefore be unlawful for the U.S. to receive and/or rely on intelligence where the U.S. knows or should know that there was a real risk of the intelligence being obtained from torture.”