A video of a man believed to be a missing Japanese journalist in Syria has been posted online, in an apparent demand from his captors to the Japanese government.

In the clip, Jumpei Yasuda addresses his family and says he cannot speak with them, his hair looking longer and more dishevelled than in a previous photo taken shortly before he went missing around July last year.

الصحفي الياباني ياسودا جومبي يوجه رسالة الى اهله واصدقائه من اجل المساعدة باطلاق سراحه. يذكر ان ياسودا خطف في منتصف العام الماضي في ريف جسر الشغور الشمالي. Posted by ‎طارق عبد الحق‎ on Wednesday, March 16, 2016

He says: "Hello, I’m Jumpei Yasuda. Today is my birthday, 16th of March. They told me that I can speak what…I want freely and I can send a message through this to anyone. I love you, my wife, father, mother and brother. I always think about you. I want to hug you. I want to talk with you. But I can’t anymore.

"When you are sitting wherever you are in a dark room, suffering with pain, there is still no one. No one answering. No one responding. You are invisible. You are not exist. No one care about you."

A picture of Jumpei Yasuda sent to Kyodo News via email on June 23, 2015, before his departure to Syria, with the message reading, "I will smuggle myself into Syria from now." Image: Kyodo

According to Kyodo News, the man who uploaded the video of Yasuda on Twitter and Facebook received it from al-Qaeda's Syrian branch Nusra Front, which is holding him and want to demand ransom from the Japanese government.

Japan reportedly said on Thursday it is investigating the footage.

France-based nonprofit group Reporters Without Borders (RWB) posted a circular in December that announced Yasuda's alleged kidnapping, and said those holding him had started a countdown for a ransom payment, and were threatening to kill him or sell him to another militant group.

However, RWB withdrew the press release a week later with apologies to Yasuda's family, fearing that the announcement would endanger the freelance war correspondent's life.

Yasuda was previously held hostage in 2004 in Iraq by gunmen when he was there reporting on the fighting. He was released unharmed about a week later.

Two Japanese hostages released in Iraq, aid worker Nobutaka Watanabe, left, and freelance journalist Jumpei Yasuda arrive at Narita airport, April 20, 2004. Image: AP

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