Russian forces captured a British mercenary who was fighting alongside the Ukrainian army in the Kursk region of Russia. This area is still partly controlled by Ukrainian forces, according to a security source speaking to Russia's RIA news agency.

"A mercenary from Great Britain, who called himself James Scott Rhys Anderson, was captured. He is now giving evidence," the Russian source told RIA in remarks published on Sunday. A video shared on unofficial pro-war Russian Telegram channels on Sunday shows a young man with a beard, dressed in military clothes and with his hands apparently tied behind his back. He says in English that his name is James Scott Rhys Anderson and that he used to serve in the British Army.

However, News agency Reuters could not independently confirm the video, and reports from RIA and other media outlets could not be verified either. The timing of the video is unclear. The British Foreign Office has not yet responded to a Reuters request for comment, as it was made outside of office hours. The Foreign Office stated that it was "supporting the family of a British man following reports of his detention," according to an earlier BBC report.

Ukrainian forces launched a surprise attack in the Russian border region of Kursk in August and took control of some areas. However, Ukraine announced over the weekend that it has lost more than 40% of the territory it had captured, as Russian forces have carried out multiple counterattacks.