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© Getty Images / Oleksii Liskonih
A Japanese citizen has been detained in Vladivostok while trying to obtain classified material about Russia's military capabilities, officials have confirmed. He has since left the country.

The suspected spy was arrested on Saturday while trying to obtain secrets about what military assets Moscow has in the Far East, the Russian foreign ministry said. The Japanese national, who was in Russia on a journalism-related visa, was instructed to leave the country within 72 hours. He obliged and departed on Sunday.

"The Japanese diplomats accredited in Russia have been issued with a note of protest, stating that such activities are not acceptable," the ministry cautioned.

The news comes amid an unfolding espionage scandal involving another Japanese citizen, who was arrested for allegedly passing a Japanese phone carrier's proprietary information to the Russian trade mission in Tokyo.

Yutaka Araki, 48, is suspected of abusing his position at SoftBank, his former employer, to obtain trade secrets. The alleged theft happened in February last year, Japanese police said.

SoftBank said the stolen materials were "low in confidentiality" manuals for communication equipment and offered an apology for the incident. The suspect was fired in mid-December.

The Russian embassy in Japan said it regretted Tokyo's move to join the "anti-Russian speculation trendy in the West on the hackneyed topic of spy mania."