The United States lashed out at Russia on Monday over the sentencing of American citizen Paul Whelan to 16 years in a high security prison on charges of spying. “The United States is outraged by the decision of a Russian court today to convict US citizen Paul Whelan after a secret trial, with secret evidence, and without appropriate allowances for defense witnesses,” Secretary of state Mike Pompeo said in a statement. Mr Pompeo said Russia's treatment of the former US Marine was appalling and urged his immediate release. “Russia failed to provide Mr Whelan with a fair hearing before an independent and impartial tribunal; and during his detention has put his life at risk by ignoring his long-standing medical condition; and unconscionably kept him isolated from family and friends. We demand Paul Whelan’s immediate release.” Mr Whelan, 50, who holds US, British, Canadian and Irish passports, was detained by Russian authorities in December 2018 during a visit to Moscow for a friend’s wedding. Russian authorities accused him of spying and said he was caught with a flash drive containing classified information. The former Marine said it was a “sting operation” and pleaded not guilty. In court on Monday, Mr Whelan, standing behind a glass screen, held up a paper that read "Sham trial," "No human rights" and "Paul's life matters". According to the <em>New York Times</em>, his lawyer Vladimir Zherebenkov will appeal the verdict. Moscow could also be seeking a prisoner swap with the US that would release two Russian citizens, Viktor Bout and Konstantin Yaroshenko, who are jailed in the US and accused of arms and drugs dealing. US Ambassador to Russia John Sullivan decried Monday’s decision calling it “a mockery of justice”. "If they can do this to Paul, they can do this to anyone. A secret trial with the inability to defend oneself, it's a mockery of justice in addition to the fact that he's been horribly mistreated," he said. He added that the decision would hurt US-Russian relations.