A representative of Russia-backed separatists in eastern Ukraine said on July 15 that Briton Paul Urey, who was captured by forces fighting against pro-Kyiv troops in Ukraine, has died in detention.
There was no immediate confirmation from British authorities.
"He died on July 10," Darya Morozova, a representative of a separatist group in Donetsk, said via Telegram.
She said the 45-year-old died "due to illness and stress."
Morozova also said Urey suffered from diabetes, a claim that could not immediately be confirmed.
Urey's capture in April by anti-Kyiv forces in the midst of Russia's all-out invasion of Ukraine that began in late February led to Russian television showing his interrogation in handcuffs.
Nongovernmental organizations and colleagues have described Urey as an aid volunteer.
The Russia-backed fighters have described him as a "professional" soldier and had accused him of "mercenary activities."
Urey's distraught daughters told Sky News in May that they were "preparing for the worst."