A Japanese national has been detained in Iran and must be swiftly released, the Japanese government said on Wednesday.
The person was detained on January 20, Deputy Chief Cabinet Secretary Masanao Ozaki told reporters. He gave no further details.
Radio Free Europe earlier reported that Shinnosuke Kawashima, the Tehran bureau chief of Japan's public broadcaster, NHK, had been arrested by Iran and transferred to a Tehran prison.
NHK declined to confirm that an employee of theirs had been detained.
"As NHK, we always act with the safety of our staff as the top priority. There is nothing we can answer at this stage," a spokesperson said.
UK condemns 10-year sentence for couple in Iran espionage case
In addition, last week, British foreign minister Yvette Cooper condemned as "totally unjustifiable" the 10-year sentence given to a British couple in Iran for spying, saying the government would continue to press for their release.
Craig and Lindsay Foreman had been charged with espionage after Iran accused them of gathering information in several parts of the country.
"We will pursue this case relentlessly with the Iranian government until we see Craig and Lindsay Foreman safely returned to the UK and reunited with their family," Cooper said in a statement.