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On Saturday, Japanese Prime Minister Shinzo Abe pledged $200 million in non-military assistance for countries battling ISIS.
"I will pledge assistance of a total of about 200 million US dollars for those countries contending with ISIL, to help build their human capacities, infrastructure, and so on," he added.
In the video, a black-clad militant brandishing a knife addresses the camera in English standing between two hostages wearing orange jumpsuits.
The voice of the ISIS militant appears to be that of "Jihadi John," who is believed to have beheaded two American journalists and a British aid worker.
"You now have 72 hours to pressure your government into making a wise decision by paying the £200 million ($302,930,000) dollars to save the lives of your citizens," he says.