A South Korean citizen has been arrested in Russia on suspicion of espionage, Russian state news agency TASS reported Monday.

TASS quoted law enforcement agencies as saying the man, whom it named as Park Won-soon, had been detained in the far eastern city of Vladivostok before being transferred to Moscow for “investigative actions.”

The state news outlet said it was the first such case against a South Korean national. It did not provide any details on the nature of the alleged spying.

South Korea’s Ministry of Foreign Affairs said in a statement its consulate has been providing assistance since it became aware of the arrest. It declined to give more details as the matter was currently under investigation.

Russia regards South Korea as an “unfriendly” country because of Seoul’s support for Western sanctions against Moscow over the war in Ukraine.

At the same time, Russia has cultivated closer relations with North Korea, which the United States says is providing munitions to Moscow for use in the war. North Korea and Russia have denied this, although they have pledged to strengthen military cooperation.