A Russian court sentenced a 72-year-old American to nearly seven years in prison Monday after he was convicted on charges of fighting as a mercenary in Ukraine. 

Investigators alleged during a closed-door trial that Stephen Hubbard of Michigan was paid $1,000 a month to enlist in a Ukrainian defense unit in Izyum, a city in the eastern part of the country, where he had been residing since 2014, according to Reuters. 

The news agency cited Russian investigators and state media as saying that Hubbard was trained and given weapons and ammunition after he allegedly signed up for the mercenary unit in February 2022. Two months later, he reportedly was detained by Russian soldiers and then pleaded guilty to charges of fighting as a mercenary. 

Hubbard was sentenced to six years and 10 months in prison. He is the first American known to have been convicted on charges of fighting as a mercenary in the Ukrainian conflict, according to the Associated Press.  

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The charges carry a potential sentence of 15 years, but prosecutors asked that his age be taken into account along with his admission of guilt, Russian news reports said. 

Last month, Hubbard’s sister Patricia Hubbard Fox and another relative told Reuters that he held pro-Russian views and was unlikely to have fought in battle at his age. 

Russian state media is saying Hubbard plans to appeal the verdict. The U.S. State Department did not immediately respond to a request for comment from Fox News Digital.

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A court in the Russian city of Voronezh also sentenced American Robert Gilman on Monday to seven years and one month for allegedly assaulting law enforcement officers while serving a sentence for another assault. 

Gilman, a U.S. Marine veteran, was arrested in 2022 for causing a disturbance while intoxicated on a passenger train, and then allegedly assaulted a police officer while in custody, Russian news reports say. He is already serving a 3 1/2-year sentence on that charge. 

State news agency RIA-Novosti said that last year, he assaulted a prison inspector during a cell check, then hit an official of the Investigative Committee, resulting in the new sentence.

The Associated Press contributed to this report.