Image copyright Reuters Image caption Jumpei Yasuda, pictured here before he went to Syria, went missing shortly after crossing over from Turkey

Japan says it believes in the authenticity of a newly released photo purporting to show a Japanese journalist held hostage in Syria.

The image, posted online on Sunday, shows a heavily bearded Jumpei Yasuda holding a sign saying: "Please help me. This is my last chance."

Mr Yasuda is believed to have been seized by the jihadist group al-Nusra Front, allied to al-Qaeda, in July.

Japan's government said it was doing everything it could to help him.

Foreign Minister Fumio Kishida said on Monday: "We believe the photo is of Yasuda."

Cabinet Spokesman Yoshihide Suga said the government was "making use of a broad net of information and doing everything we can to respond".

In March, a video emerged of Mr Yasuda apparently accusing the Japanese government of ignoring him.

Last year, the so-called Islamic State (IS) in Syria beheaded Japanese war correspondent Kenji Goto and Haruna Yukawa, leading to accusations that Japan had not done enough to save them.

Japan's Kyodo news agency quoted an unnamed source claiming to be a mediator for the Nusra Front saying Mr Yasuda would be passed to IS if the government did not negotiate.