Up to 2,000 males in Yemen, including children, were detained, disappeared, or tortured in secret prisons run by the United Arab Emirates as part of its widespread hunt for al-Qaida and ISIS militants. And the U.S. military interrogated detainees nearby.

That’s according to a pair of bombshell reports by the Associated Press and Human Rights Watch released Thursday. The AP’s investigation details the horrific abuse suffered by those captured at 18 camps dotted across southern Yemen; HRW backs up those claims, reporting that four children were among the 49 cases of arbitrary detainment, forced disappearance, torture, and abuse that it documented over the course of its year-long investigation.

Among the more grisly torture methods used in the camps was a technique known as the grill, which involves tying victims to a spit like a roast and spinning them over a fire. The black sites that the AP uncovered are housed in a variety of locations, including military bases, private villas, and in one case, inside a nightclub.

The UAE has denied all allegations. “There are no secret detention centers and no torture of prisoners is done during interrogations,” a government spokesperson told AP.

But lawyers and families interviewed in both reports rebuffed the Gulf nation’s claims, pointing to hundreds of instances in which men have been disappeared, tortured, and abused.

“You don’t effectively fight extremist groups like al-Qaeda or ISIS by disappearing dozens of young men and constantly adding to the number of families with ‘missing’ loved ones in Yemen,” Sarah Leah Whitson, Middle East director at HRW, said in the report. “The UAE and its partners should place protecting detainee rights at the center of their security campaigns if they care about Yemen’s long-term stability.”

U.S. officials confirmed to the AP that U.S. forces do in fact participate in interrogations of detainees in Yemen, but they denied knowing of or participating in any human rights abuses — actions that would put the U.S. on the wrong side of international law.

“We would not turn a blind eye, because we are obligated to report any violations of human rights,” chief Defense Department spokesperson Dana White told the AP.

The U.S. is facing mounting pressure from the international community for its increasingly muddled role in Yemen, where the U.S. is fighting al-Qaida and supporting Saudi Arabia’s war against Houthi rebels.

The U.S. military significantly ramped up its counter-terror airstrikes in 2017, raising concerns over whether it was taking the necessary precautions to avoid civilian casualties. But more controversial has been its role in supporting the Saudi-led coalition’s actions in Yemen, which the U.N. says is to blame for the majority of civilian casualties in the country’s two-year civil war.

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