The Islamic State popularly known as ISIS has released a new video in which they threatened to kill two Japanese hostages unless they receive a ransom of $200 million within 72 hours.

Reports say the video was released two days after Japan's Prime Minister, Shinzo Abe, pledged the same amount in non-military support for countries fighting ISIS.

It was gathered that the footage was posted on militant websites connected with the terror group.

The video featured a fighter with British-accent suspected to be 'Jihadi John' who appeared in the beheading videos of David Haines, Alan Henning, James Foley, and Steven Sotloff.

The Japanese hostages in the video are identified as Kenji Goto Jogo - a journalist, Haruna Yukawa - a military company operator.

Daily Mail reports that the militant said the Japanese were targeted for supporting Western military efforts against ISIS.

Japan's Foreign Ministry's anti-terrorism section has seen the video and analysts are assessing its authenticity, a ministry official said.

The official spoke on condition of anonymity because of department rules.

The militant with a British accent in the video said the Japanese were targeted for supporting Western military efforts against the Islamic State group, which now holds a third of Iraq and Syria under its self-declared caliphate.

He says: 'You have proudly donated $100 million to kill our women and children, to destroy the homes of the Muslims.'

A Japanese citizen believed to be Yukawa, a private military company operator in his early 40s, was kidnapped in Syria in August, 2014.

His reason for going to Syria is yet to be known.

Goto is a Japanese journalist who went to report on Syria's civil war last year.