Authorities in Iraq's autonomous Kurdish region on Monday handed over a Japanese national detained last month on suspicion of ties to ISIL.
Media reports say Kosuke Tsuneoka, 47, is a freelance journalist who was covering the battle to take the city of Mosul from the armed group.
"A Japanese national, Mr Kosuke Tsuneoka - also known by the nom de guerre Shamil K Tsuneoka - was detained ... for links to the Islamic State," the Kurdistan Regional Security Council said in a statement.
"An investigation by our Counter-Terrorism Department found he was in contact with ISIL members through his smartphone."
Tsuneoka was taken into custody on October 27 by Kurdish forces near Mount Zardak, a strategic hill east of Mosul, the council said.
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After his release, Tsuneoka took to Twitter to explain what happened.
He said he had been arrested because he was carrying a key chain with an ISIL logo that he obtained on an earlier reporting trip.
"But this became a problem at a security check for a presidential press conference. I was suspected as an IS member and arrested and interrogated. I had explained this to the authorities, and I do hope they believe my innocence," Tsuneoka said.
He denied a media report that said he served as a translator for ISIL fighters and received a medal.
"That's terrible. I don't understand Arabic at all," he tweeted.
Mosul is ISIL's last major stronghold in Iraq. A coalition of Iraqi forces, including the Kurdish Peshmerga, launched a huge multi-pronged offensive to retake the city on October 17.
The KRSC said Tsuneoka left the country on Monday via the main airport in Erbil, the capital of Iraq's Kurdish region.
