WASHINGTON, June 15. /TASS/. The United States is outraged by the verdict of US citizen and former marine Paul Whelan over espionage charges against Russia and demands that he be immediately freed, US Secretary of State Mike Pompeo issued a statement Monday.

"The United States is outraged by the decision of a Russian court today to convict U.S. citizen Paul Whelan," he underlined. "We demand Paul Whelan’s immediate release," Pompeo added.

Earlier, Kremlin Spokesman Dmitry Peskov stressed that Whelan faced charges that were "proven in and accepted by the court." At the same time, he would not comment on the court’s decision and Whelan’s future.

Whelan’s defense attorney Olga Karlova earlier told TASS that her client had a hernia surgery. The Russian Foreign Ministry, meanwhile, said that Whelan had received immediate treatment.

US national Paul Whelan, global security chief at BorgWarner, a Michigan-based automotive components company, was detained by Russian security officers on December 28, 2018 in Moscow while on a spy mission. According to investigators, the man was carrying a USB drive containing state classified information. A criminal investigation was opened against him on espionage charges carrying a punishment of up to 20 years in jail. Whelan denies committing the crime, while his defense attorneys insist the case is fabricated. Along with US citizenship, Whelan also holds British, Canadian and Irish passports. On Monday, the Moscow City Court delivered a guilty verdict and convicted Whelan to 16 years behind bars.