MOSCOW — The brother of an American convicted of espionage in Russia said Thursday that his imprisoned sibling is suffering sleep deprivation at a prison colony where he is serving a 16-year sentence.

David Whelan said his brother, Paul, complained that he was being woken up at approximately 2-hour intervals every night over the past few weeks. The practice apparently began because someone in the Russian system deemed Paul Whelan a flight risk, his brother said.

"It is ridiculous to label someone like Paul - a foreigner lacking in money and language skills, let alone family and other connections in Russia - a flight risk," David Whelan said.

The U.S. Embassy has protested to the Russian Foreign Ministry but not received a response, he said.

Paul Whelan, a former corporate security executive from Michigan, was arrested in Moscow in December 2018. His lawyer said Whelan was handed a flash drive that had classified information on it that he didn't know about.

Whelan was convicted in June and sentenced to 16 years in prison. He was sent to a prison colony in Mordovia, about 350 kilometers (210 miles) east of Moscow.