Russia’s top domestic security agency said Wednesday it has detained a German national who faces charges after allegedly serving in the Ukrainian army.

The Federal Security Service, or FSB, the successor agency to the Soviet KGB, didn't give the man's name or any other identifying details, and did not say where or when the man was taken into custody.

According to the FSB statement, the man served in Ukraine's military in 2016-18 and later signed a three-year contract in 2025 but then deserted after not getting paid. It alleged he also was involved in hostilities in Afghanistan as part of the German contingent there, as well as in Somalia and Syria.

The man faces criminal charges in Russia of mercenary activities, the FSB said.

The FSB's allegations could not be independently verified.

Kathrin Deschauer, a spokeswoman for the German Foreign Ministry, said Wednesday that the German authorities were aware of the report. She refused further comment, adding only that “our priority is first and foremost to clarify the facts, which we are of course pursuing.”

Last week, the FSB said it detained a Swedish man, who was suspected of sabotage, on charges of illegally crossing the border, and also announced it had arrested a Japanese journalist who was suspected of spying.

In recent years, Russia has arrested a number of foreigners — mainly Americans — on various criminal charges and then released them in prisoner swaps with the U.S. and other Western nations.

The largest exchange since the Cold War took place in August 2024, when Moscow freed journalists Evan Gershkovich and Alsu Kurmasheva, fellow American Paul Whelan and Russian dissidents in a multinational deal that set two dozen people free.

More Americans imprisoned in Russia were released after U.S. President Donald Trump returned to office in January 2025, with the latest announcement Wednesday by U.S. envoy Steve Witkoff during talks with Russian President Vladimir Putin.

Witkoff thanked Putin for freeing Stephen Hubbard, a 74-year-old former teacher from Michigan who spent more than four years behind bars in Russia. In 2024, Hubbard was convicted on charges of fighting as a mercenary in Ukraine and sentenced to nearly seven years in prison. The U.S. had designated him as wrongfully detained.

Kremlin spokesman Dmitry Peskov said Putin made the decision to release Hubbard out of “humanitarian considerations.”

——

Daniel Niemann in Cologne, Germany, contributed.