MOSCOW — A court in Russia has upheld lengthy prison sentences handed down to a couple convicted on high treason charges that stemmed from a wedding photo that included an officer of the Federal Security Service (FSB).

Maria Bontsler, a lawyer for Antonina Zimina, told RFE/RL that the Moscow Court of Appeal had rejected the appeals of Zimina and her husband, Konstantin Antonets, on April 20.

The couple, from Russia’s Far Western Kaliningrad exclave, was found guilty of spying for Latvia in late December 2020.

The couple were charged with treason after state prosecutors accused them of sharing a photograph with Latvia of a counterintelligence officer from the FSB who had attended their wedding.

Investigators later additionally charged them with passing classified information to a foreign country.

Zimina was sentenced to 13 years, while Antonets was handed a 12 1/2-year prison sentence. The couple has denied any wrongdoing ever since they were first arrested in July 2018.

Their trial was held behind closed doors in May 2020.

In recent years, the number of cases of alleged high treason has increased dramatically in Russia.

One of the latest high-profile high treason cases involves Ivan Safronov, a journalist and an aide to the Roskosmos space agency chief Dmitry Rogozin.

Safronov was arrested on July 7 and later charged with passing classified materials to the Czech Republic.