The U.N. Assistance Mission in Afghanistan said it interviewed 13 detainees from a group of 53 recently rescued from the Taliban, mainly members of Afghan forces but also civilians and government officials captured by the insurgents.
The group was freed on April 25 when Afghan troops raided a Taliban-run detention facility in the Khas Uruzgan district in southern Uruzgan province.
Most of the captives were held since 2018, with three since 2016, the UNAMA statement said, adding they were kept in poor conditions and subjected to forced labor. It cites the detainees as saying that the Taliban killed some of their captives.
"I am gravely concerned about these serious allegations of ill-treatment, torture and unlawful killing of civilians and security personnel, as well as the deplorable conditions of detention," said Tadamichi Yamamoto, the head of UNAMA.
The detainees were shackled while in captivity and almost all said they were beaten. The Taliban told them it was punishment for supporting the government, working with the Americans or fighting the insurgents.
The U.N. statement comes as Washington's peace envoy, Zalmay Khalilzad is pressing ahead with talks with the Taliban, who refuse to negotiate directly with the Kabul government.
The talks so far have focused on a timetable for U.S. troop withdrawal as well as Taliban guarantees that they won't harbor terrorist groups or allow Afghanistan to be used as a staging ground for global terrorist attacks.
The conflict in Afghanistan has cost more than 2,300 American lives and hundreds of billions in taxpayer dollars. As the war approaches its 18th year, 14,000 U.S. troops are still in Afghanistan, and senior intelligence officials have repeatedly warned that the country remains fragile and could once again become a terrorist haven.
"The United Nations reminds the Taliban that international humanitarian law applicable to international and non-international armed conflicts provides that all persons who do not take direct part in hostilities, or who have ceased to do so, must always be treated humanely," said Richard Bennett, UNAMA's chief for human rights.
Since 2011, UNAMA has monitored and reported on the treatment of conflict-related detainees.