Video Purports to Show Beheading of US Journalist Steven Sotloff

A video showing the purported beheading of US journalist Steven Sotloff held hostage by Islamic State has been released online, the Washington Post reported on Tuesday.

The video attributed to the Islamic State (IS) marks the showing of second such execution in as many weeks by the group that controls parts of Iraq and Syria and has threatened to kill other captives in retaliation for US air strikes against IS fighters.

Sotloff, a 31-year-old freelance journalist, had written for Time magazine, Foreign Policy and other publications. He disappeared in Syria last year.

Last month he appeared at the end of a video which showed fellow US journalist James Foley being beheaded.

Sotloff's family issued a statement saying it believed he had been killed. The White House said US officials were checking the reports of Sotloff's death.

The video showing a bound Sotloff being held at knifepoint by a militant dressed in black against a desert backdrop was obtained by the SITE Intelligence Group, an organization that tracks jihadist web postings.