A Russian court has upheld an earlier ruling to keep a former U.S. Marine in a Moscow jail for three more months as he faces espionage charges.

Michigan resident Paul Whelan, who also holds British, Irish and Canadian citizenship, was arrested in a hotel room in the Russian capital at the end of December.

The Moscow City Court on Thursday upheld the ruling that ordered keeping Whelan in jail at least until the end of May.

Paul Whelan, a former U.S. Marine, who was arrested in Moscow at the end of last year, attends a hearing in a court in Moscow, Russia, Thursday, March 14, 2019. (AP Photo/Dmitry Serebryakov)
Paul Whelan, a former U.S. Marine, who was arrested in Moscow at the end of last year, attends a hearing in a court in Moscow, Russia, Thursday, March 14, 2019. (AP Photo/Dmitry Serebryakov)

Whelan’s lawyer has said his client was handed a flash drive which had on it classified information he didn’t know about. He confirmed on Thursday that Whelan is accused of spying for the United States.

A spying conviction in Russia carries a possible sentence of up to 20 years in prison.

Paul Whelan, a former U.S. Marine, who was arrested in Moscow at the end of last year, attends a hearing in a court in Moscow, Russia, Thursday, March 14, 2019. (AP Photo/Dmitry Serebryakov)
Paul Whelan, a former U.S. Marine, who was arrested in Moscow at the end of last year, attends a hearing in a court in Moscow, Russia, Thursday, March 14, 2019. (AP Photo/Dmitry Serebryakov)
Paul Whelan, a former U.S. Marine, who was arrested in Moscow at the end of last year, attends a hearing in a court in Moscow, Russia, Thursday, March 14, 2019. (AP Photo/Dmitry Serebryakov)
Paul Whelan, a former U.S. Marine, who was arrested in Moscow at the end of last year, attends a hearing in a court in Moscow, Russia, Thursday, March 14, 2019. (AP Photo/Dmitry Serebryakov)