People walk past television screens displaying a news program, about an Islamic State video showing Japanese captive Kenji Goto, on a street in Tokyo January 28, 2015. [Photo/Agencies]

In the first of three videos purportedly of Goto, released last week, a black-clad masked figure with a knife said Goto and Yukawa would be killed within 72 hours if Japan did not pay Islamic State $200 million.

The captor resembled a figure from previous Islamic State videos whose threats have preceded beheadings.

A video on Saturday appeared to show Goto with a picture of a decapitated Yukawa, saying his captors' demands had switched to the release of al-Rishawi.

Tuesday's video featured an audio track over a still picture that appeared to show Goto holding a picture of a now bearded Kasaesbeh.

Officials involved in the crisis say Tokyo knew for months that Islamic State militants were holding two Japanese men captive, but appeared ill-prepared when the group set a ransom deadline and purportedly killed one of them.