In a statement late Saturday, the White House harshly condemned what US President Barack Obama described as a "heinous murder."
"Our thoughts are with Mr. Goto’s family and loved ones, and we stand today in solidarity with Prime Minister Abe and the Japanese people in denouncing this barbaric act," the statement read.
It was echoed by British Prime Minister David Cameron, who also decried the beheading video that came less than a week after the purported decapitation of another Japanese man, Haruna Yukawa.
"I utterly condemn what appears to be the despicable and appalling murder of Kenji Goto. It is a further reminder that Islamic State is the embodiment of evil, with no regard for human life."
Also condemning the beheading was French President Francois Hollande, who said he "resolutely condemned the brutal murder of Japanese citizen Kenji Goto by IS. France stands in solidarity with Japan in this new ordeal."
For his part, Australian Prime Minister Tony Abbot said that "if true, this will be a terrible shock for the people of Japan, an unspeakable horror for the family and this just demonstrates how important it is that all countries do what they reasonably can to disrupt and degrade this death cult which has ushered in a new dark age over parts of the Middle East."
Meanwhile, Japan's Chief Cabinet Secretary Yoshihide Suga has said that Tokyo would not render logistical support to the anti-Islamic State coalition's airstrike effort in Syria.
The statement came after Japanese Defense Minister Gen Nakatani ordered more efforts to provide for the security of the Japan Self-Defense Force deployed abroad, including within the framework of the UN's peacekeeping operations.