The brother of a British man captured by Russia after fighting for the Ukrainian army has said it could take months to secure his release.
Aiden Aslin, 28, from Nottingham, was taken prisoner in Mariupol after his unit ran out of ammunition and food.
His brother Nathan Wood said he is confident Aiden will be released but fears it “could all take days, weeks, months”.
The 25-year-old care worker added: “We have to be patient but we feel more confident now that Aiden will be released.
“The Prime Minister is aware Aiden has been taken prisoner of war. It gives us a bit of hope but it is now a waiting game.
“There needs to be a positive outcome and now the Russians are talking about him potentially being freed in a prisoner swap, he is hopefully being treated with humanity.
“They have made their demands clear. Hopefully they are treating him like a prince, they don’t want to show him with scratches and bruises because it could harm their chances.
“This could all take days, weeks, months but the Ukrainian and Russian governments appear to be talking and now we need Britain to offer some support.”
Several videos had initially surfaced via Russian media of Mr Aslin and fellow British fighter Shaun Pinner who was also captured while defending the city of Mariupol.
In the clips, the men, who had lived in Ukraine for four years and served in its forces before the invasion began, appear to spout Kremlin talking points and disavow their former actions, leading to fears that they were being coerced into speaking out.
The captive begged the Prime Ministerto help bring him home in exchange for Ukraine releasing pro-Russian politician Viktor Medvedchuk.
“We would call on Russia and Putin to treat any prisoners of war properly in line with conventions and laws," a spokesman for the prime minister said.
When asked specifically about Aslin in the Commons, Mr Johnson appealed to Moscow to treat him "humanely".
But Maria Zakharova, the Russian foreign ministry spokeswoman, has accused the prime minister of having “no interest” in what happened to the men.
"Don’t pretend to be worried. You have absolutely no interest in the fate of the British people in trouble. They did not have fun with you at parties in Downing Street, and, therefore, they will not wait for your patronage," Ms Zakharova said.
She described the men as "victims of British propaganda [who] went as mercenaries to Ukraine to kill people".