LONDON: A video posted online Tuesday purported to show the beheading of US journalist Steven Sotloff by the Islamic State group.

British Premier David Cameron condemned the video as “absolutely disgusting, despicable act.”

If the video is genuine, “we are sickened,” US State Department spokeswoman Jen Psaki said.

Sotloff, 31, had last been seen in Syria in August 2013 until he appeared in a video released online last month by the Islamic State that showed the beheading of fellow US journalist James Foley.

In Tuesday’s video entitled “A Second Message to America,” Sotloff appears in a similar jumpsuit. The fighter who beheads Sotloff in the video called it retribution for Obama’s continued airstrikes against the group in Iraq. “I’m back, Obama, and I’m back because of your arrogant foreign policy toward the Islamic State ...,” the fighter said.

At the end of the video, he threatened to kill a third captive, a Briton, David Cathorne Haines. Sotloff’s mother had pleaded for his release last week in a video directed at the Islamic State group.