TOKYO (AP) — Japan’s government said Wednesday that a Japanese national has been detained in Tehran since January and demanded the Iranian authorities release them swiftly.

Deputy Chief Cabinet Secretary Masanao Ozaki, asked about foreign media reports about the case, only confirmed that the Japanese citizen was taken into custody on Jan. 20 but gave no further details, citing privacy issues.

Ozaki said the government is in contact with the detainee and their family members, while providing necessary support.