The Japanese government is trying to contact the Islamic State group through an email address of the group used when it demanded a ransom from the wife of one of the Japanese hostages, Kenji Goto.
But a government source said no response had been received from the group as of Thursday night.
According to the source, the wife of Goto, who is being held captive by the armed group along with private security contractor Haruna Yukawa, received an email in November notifying the family of the kidnapping of the freelance journalist. Since then, around 10 emails have been sent to her.
The emails, ostensibly from the armed group, included information that only Goto and his family could have known. Information on Goto's whereabouts, or pictures or videos of him, have not been included, the source said, adding that no death threats have been received, either.
In January, the group issued a demand to Goto's wife for around ¥2 billion in euro currency as a ransom, the source said. Earlier media reports said the ¥2 billion ransom demand had been made to her in December.