Two British men captured by Russian forces while fighting alongside Ukrainian soldiers face 20 years in prison, according to a video shared by Russian state media. Aiden Aslin and Shaun Pinner, who were serving in the Ukrainian military, were detained in April while fighting in Mariupol. The Britons appeared in court in the separatist Donetsk People’s Republic (DPR). Aslin, 28, and Pinner, 48, are said to have admitted “training in order to carry out terrorist activities”. In footage shared by Ria Novosti, a Russian state news agency, on social media on Wednesday, an interpreter can be heard asking Aslin, from Newark, Nottinghamshire, if he would “plead guilty” to an offence, to which he replied: “Yes.” The charge carries a term of 15 to 20 years’ imprisonment with restriction of freedom for a term of one to two years or life imprisonment, according to Ria Novosti. The video appeared to show the two Britons in the dock in the pro-Russian territory’s supreme court alongside a third man, reported to be Saaudun Brahim, a Moroccan national who was also captured. Pinner, from Watford and Bedfordshire, is also said to face a longer term and possibly the death penalty after allegedly admitting to “seizing power by force”. The men are understood to be the first Ukrainian soldiers to be tried by pro-Russian forces. It comes hours after Conservative MP Robert Jenrick said Aslin should be returned to Ukraine at the earliest opportunity, potentially through a prisoner exchange, and condemned the “trumped-up charges” faced by both Britons. The former housing secretary and Newark MP told BBC Radio 4’s World At One programme: “This is a British citizen, but who also holds Ukrainian nationality, is married to a Ukrainian, joined the Ukrainian armed forces in the normal way prior to [Vladimir] Putin’s illegal invasion, and has been serving in the armed forces. “He was taken prisoner by Russian forces and in accordance with international law and the Geneva convention, he should be being held appropriately and returned to Ukraine at the earliest possible opportunity, possibly through a prisoner exchange. “Instead of that Putin’s regime have chosen to put him and another British national, Shaun Pinner, on trial on trumped up charges, no evidence whatsoever. “This is, I’m afraid, a completely outrageous breach of international law and it should be condemned.” On Monday, Dominic Raab, the justice secretary, said the Foreign Office will “make all the representations” on Aslin’s behalf and his family also issued a statement calling for his release. The statement said: “We are currently working with the Ukrainian government and the Foreign Office to try and bring Aiden home. Aiden is a much-loved man and very much missed, and we hope that he will be released very soon.” Ukraine has sentenced three Russian soldiers to prison for war crimes tied to the Russian offensive that began on 24 February. Vadim Shishimarin, 21, was sentenced to life in prison for killing a 62-year-old civilian in Ukraine’s north-eastern Sumy region early in the war. Two soldiers, Alexander Bobikin and Alexander Ivanov, were each sentenced to more than 11 years in prison for shelling attacks on population centres that “violated the laws and customs of war”.