MOSCOW (AP) — An American man kept behind bars in Russia on spying charges has appealed to U.S. President Donald Trump for help.

Paul Whelan, who also holds British, Irish and Canadian citizenship, appealed to Trump in a Moscow court on Thursday to intervene in his case and "defend" him.

Whelan was arrested in a hotel room in the Russian capital at the end of December and charged with espionage, which carries up to 20 years in prison in Russia.

The former U.S. Marine denies the charges. His lawyer has said that his client was handed a flash drive that had classified information on it that he didn't know about.