Russian state-run broadcaster RT on Tuesdayshowedrare footage of former United States Marine Paul Whelan inside a penal colony, in what his brother said was his first public appearance in over three years.The United States has designated Whelan who is serving a 16-year sentence on espionage charges in Russias remote republic of Mordovia as wrongfully detained.RTs six-minute report showed Whelan, who was dressed in a black prison jacket and hat, along with other inmates inside a prison yard, a food hall and a workshop performing penal labor.Whelan declined to be interviewed, telling RT correspondent Igor Zhdanov:I cant answer any questions.His brother David said the footage was filmed in May, when prison staff retaliated against him for declining to participate in RTs interview, according to Reuters.Today was the first time Ive seen what he really looks like since June 2020, the jailed American's brother said in an email.The Biden administration has beenexploring options to exchange Whelan and other Americans jailed in Russia for Russian nationals imprisoned in the United States and other allied countries.A Moscow court found Whelan guilty of receiving classified information in 2018 and sentenced him to 16 years in a penal colony in June 2020.Whelan, who is also a British, Canadian and Irish citizen, denies the charges.