The UK government has promised to do all it can to assist a former British soldier fighting for Ukraine who has been taken prisoner by the Russian army.

Two videos of a man who identified himself as James Scott Rhys Anderson surfaced on Russian Telegram channels over the weekend. They featured interrogation of a bearded man in military fatigues, who had his hands tied and spoke slowly in English to give details from his biography, including that he served as a signalman in the British army between 2019 and 2023. Anderson is 22, according to the date of birth he gave in the video.

Russian news agencies confirmed a British man had been captured.

The UK foreign secretary said on Monday he had been briefed on the case. “I have been updated about that development in the last couple of days. Of course, we will do all that we can to offer this UK national all the support we can,” said David Lammy, during a break in G7 talks in Italy. A spokesperson for the Foreign Office said: “We are supporting the family of a British man following reports of his detention.”

Anderson reportedly travelled to Ukraine eight months ago to volunteer as part of the Ukrainian army’s International Legion. The exact circumstances of how he was captured remain uncertain and it is not clear when the video was filmed. The International Legion did not respond to requests for comment.

Russian bloggers claim he was taken near the village of Plekhovo in the Kursk region inside Russia. “A mercenary from Great Britain, who called himself James Scott Rhys Anderson, was captured. He is now giving evidence,” a Russian security source told the state-funded news agency RIA.

Russia traditionally treats foreigners fighting with the Ukrainian army as mercenaries and says they are not subject to standard protections offered to prisoners of war – protections that Russia regularly violates in any case.

Although there have been numerous foreign fighters taken prisoner by Russian forces in Ukraine, Anderson’s capture, if confirmed, would be the first known case of a western solider being caught inside Russia. Ukrainian forces occupied a chunk of Russian territory in an audacious offensive earlier this year, but Russian troops are pushing them back and have recaptured about 40% of the territory they had lost, amid heavy fighting.

Anderson’s father, Scott Anderson, said he had been called by his son’s Ukrainian commander to inform him about the capture, and had also seen the video. “I was in complete shock and in tears. I could see straight away it was him,” Scott Anderson told the Daily Mail.

One person who had spent time with Anderson in Ukraine said: “He is a very giggly, positive, funny and energetic person who loves to hang out with his boys. It’s very easy to talk to him even though he can be introverted in a crowd. He is observant and is a really fun and comfortable person to be around.”

Shaun Pinner, a former British solider who served with the Ukrainian army and was captured while fighting in 2022, told the Guardian that the next 10 days would be crucial for Anderson.

“It’s going to be very difficult but it will be down to his fortitude and resilience. At the end of the day he is a Ukrainian soldier, not a mercenary. That’s the bottom line,” said Pinner. “When I was captured the Russians would try to bring Britain into it at every
turn as part of their false narrative that there are British soldiers on the ground here.”

Pinner was eventually sentenced to death by a Russian proxy court in east Ukraine, but was released later in 2022 after the Russian oligarch Roman Abramovich helped broker a deal to free several British captives.

Pinner said it was important to remember that anything said publicly about Anderson could have an effect on his case and be used against him in interrogations. “The Russians will take anything that is put out and will show it to him and we have to recognise that the guys who are behind the camera are also likely to be his interrogators,” he said.

Ukraine’s International Legion was set up early in the full-scale war and consists mostly of foreign volunteers. There are also foreigners fighting in many other parts of the Ukrainian army. Early in the war, Ukrainian authorities said more than 20,000 people from 52 countries had arrived in Ukraine to fight against Russia, but since then the numbers have been classified.

Russia’s war on Ukraine has entered a new phase marked by escalated rhetoric in the weeks before Donald Trump takes over as US president. Ukraine finally received a long-requested green light from the Biden administration to fire long-range missiles into Russia to support the operation in Kursk last week; Vladimir Putin responded by firing an experimental ballistic missile at the city of Dnipro and threatening nuclear retaliation.

Russia has also kept up its drone barrage on Ukrainian cities, while a Monday morning missile attack on Kharkiv hit a residential area and injured at least 23 people, according to the city’s mayor, Ihor Terekhov. A missile also injured 10 people in the middle of the day in the southern city of Odesa, local officials said.

Ukraine has continued its own attacks on targets inside Russia linked to the Kremlin’s war effort. Ukrainian military intelligence officials told Associated Press that Ukrainian drones were responsible for explosions and a fire at an oil depot in Russia’s Kaluga region in the early hours of Monday.