From NPR - News National/International -

Reports: Islamic State Claims It Has Beheaded Second American Journalist

Sotloff talks to Libyan rebels in Libya on June 2, 2011.

In this handout image made available by the photographer American journalist Steven Sotloff (center) talks to Libyan rebels on the Al Dafniya front line on June 2, 2011 in Misrata, Libya. Sotloff was kidnapped in August 2013 near Aleppo, Syria. (Handout/Etienne de Malglaive via Getty Images)

An Islamic radical group released a video on Tuesday that purportedly shows the beheading of American journalist Steven Sotloff, according to SITE Intel Group.

The Islamic State, also known as ISIS or ISIL, had threatened Sotloff's life when it released a video showing the beheading of American journalist James Foley.

At the time, the militants said Sotloff's life depended on the actions of the U.S. government, which has been targeting the group with airstrikes to stop its offensive in Iraq.

In his regular briefing, White House Press Secretary Josh Earnest said he was "not in a position to confirm the authenticity of the video or the reports."

"Our thoughts and prayers are with Mr. Sotloff and Mr. Sotloff's family and those who worked with him," Earnest said. "The United States, as you know, has dedicated significant time and resources to try and rescue Mr. Sotloff."

Just last week, Sotloff's mother released an emotional video in which she pleaded with the Islamic State to spare her son's life.

She asked Islamic State leader Abu Bakr al-Baghdadi to grant her son amnesty, "to use your authority to spare his life and to follow the example set by the Prophet Muhammad who protected people of the Book."