Ronald Noble, the secretary general of the France-based organization, wrote in a statement Thursday of the "public killing of an innocent man" following Wednesday's confirmation that a video released earlier in the week of James Foley being beheaded was genuine.
It is a video that has "appalled people worldwide," said Interpol.
"The brutal murder of James Foley by the Jihadists of the Islamic State highlights the extent of their depravation as they conduct their campaign of terror across Syria and Iraq," he added.
Noble highlighted the need for "a multilateral response against the terror threat posed by radicalized transnational fighters" traveling to conflict zones in the Middle East.
British authorities have said that are trying to find out if a man pictured beheading Foley - who spoke with a British accent - is actually a British citizen.
Media reports have said that an estimated 12,000 foreigners from Europe and Middle Eastern countries are fighting with Islamic State militants.
The Islamic State - previously known as Islamic State of Iraq and the Levant - has declared a "caliphate" that straddles parts of Syria and Iraq, and has driven an estimated 1.2 million Iraqis from their homes.
The insurgents have particularly targeted Shiite Muslims, Turkmen, Ezidis, and Christian communities.
