(AP) - The White House says it has determined that a video showing the brutal killing of freelance journalist Steven Sotloff is authentic. 

Islamic state extremists released the video showing Sotloff's beheading on Tuesday. It comes two weeks after the militants released a video showing the killing of James Foley, another American journalist. 

In the Sotloff video, a masked militant warns President Barack Obama that continuing airstrikes against the group in Iraq will be met with the killing of more western captives.

Sotloff is a 31-year-old Miami-area native who freelanced for time and foreign policy magazines. He vanished in Syria in August 2013. 

National Security Council Spokeswoman Caitlin Hayden announced the U.S. intelligence community's assessment of the video in a statement Wednesday.

Meantime, neighbors are paying respects at the family home. The parents of Steven Sotloff didn't come out of their suburban Miami home Tuesday after Islamic state militants released a video purportedly showing his execution.

Police officers blocked the driveway as reporters gathered outside.

Neighbor Pepe Cazas said “everyone is grieving.'' He said he had been praying for Sotloff.

Sotloff's mother released a video statement last week begging the militants to release her son. He had been kidnapped over a year ago while working as a freelance reporter covering the Syrian conflict.

Sotloff attended the University of Central Florida, leaving in 2004. He published articles from Syria, Egypt and Libya in many publications, including Time.com, the World Affairs Journal and Foreign Policy.

After the video surfaced, Florida Gov. Rick Scott cancelled political events.

Scott launched a two-week tour on Labor Day and planned on Tuesday to hold his second political rally of the day at a hardware store. But during the stop Scott instead asked supporters to give a moment of silence to Sotloff. Sotloff's mother lives in the Miami area, and he attended the University of Central Florida.

Scott then called on President Barack Obama to act against the Islamic state militants who have held Sotloff in captivity.

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