(Reuters) -Returning Ukrainian prisoners of war believe their treatment by Russia while in captivity broke the Geneva Conventions, Ukrainian human rights ombudswoman Lyudmyla Denisova said on Monday. She said some former prisoners had reported that they had been kept in basements, denied food and made to take off their uniforms. Reuters could not independently verify her assertions. Russia did not immediately respond to Denisova’s comments. “Russia flagrantly violates the Geneva Convention on the Treatment of Prisoners of War. These facts were confirmed during the last liberation of Ukrainian …