China has formally arrested a Japanese man who was detained in March, according to officials from Japan’s Ministry of Foreign Affairs (MOFA) and the Japanese Embassy in Beijing.

The arrest of the Japanese national, who was reportedly an employee of a Tokyo-based pharmaceutical firm, could further rattle foreign businesses in China, which have reported feeling more unsettled this year amid a crackdown on international consulting firms on national security grounds.

“We have confirmed that the Japanese national in question has been arrested, but we have strongly appealed to the Chinese side for his early release through various levels and opportunities,” Japanese Chief Cabinet Secretary Hirokazu Matsuno said at a press conference Thursday, adding that the man, who is in his 50s, was arrested in mid-October.