The UN experts said torture included electric shocks, hoodings and mock executions and had been carried out to extract intelligence, force confessions or in response to alleged support for Ukraine
Mohammed al-Sufi was known for his criticism of Hamas leaders and their ties to Iran and was detained upon his return from Egypt last week.
Survivors of the Russia-funded torture chambers in Ukraine's Kherson told Reuters about being tortured, including electric shocks and suffocation techniques.
Ukraine's President Volodymyr Zelensky has urged Georgia to release former president and Ukrainian citizen Mikheil Saakashvili, who they claim is being tortured.