File photo of U.S. journalist Steven Sotloff

File photo of U.S. journalist Steven Sotloff (HANDOUT,, Reuters / September 2, 2014)


DUBAI (Reuters) - The Islamic State militant group released a video on Tuesday purporting to show the beheading of a second American hostage, journalist Steven Sotloff, raising the stakes in its confrontation with Washington over U.S. air strikes in Iraq.

A masked figure in the video seen by Reuters also issued a threat against a British hostage, a man the group named as David Haines, and warned governments to back off "this evil alliance of America against the Islamic State".

A statement released by Sotloff's family through a spokesman indicated the family considered the video to be authentic. "The family knows of this horrific tragedy and is grieving privately. There will be no public comment from the family during this difficult time," said the spokesman, Barak Barfi.

The purported executioner appeared to be the same British-accented man who appeared in an Aug. 19 video of the killing of American journalist James Foley, and it showed a similar desert setting. In both videos, the captives wore orange jumpsuits.

In Washington, the White House said it could not immediately confirm the authenticity of the Sotloff video. But several U.S. government sources said it appeared to be authentic.

Sotloff, a 31-year-old freelance journalist from Florida, was kidnapped in Syria in August 2013.

"I'm back, Obama, and I'm back because of your arrogant foreign policy towards the Islamic State, because of your insistence on continuing your bombings and in Amerli, Zumar and the Mosul Dam, despite our serious warnings," the masked man said in the video, addressing U.S. President Barack Obama.

"So just as your missiles continue to strike our people, our knife will continue to strike the necks of your people."

In the video, Sotloff describes himself as "paying the price" with his life for the U.S. intervention in Iraq.

The White House said late on Tuesday that Obama was sending three top officials - Secretary of State John Kerry, Defense Secretary Chuck Hagel and counterterrorism adviser Lisa Monaco - to the Middle East "in the near-term to build a stronger regional partnership" against the Islamic State militants.

U.S. officials also said Obama ordered 350 more U.S. military personnel to protect the large American embassy in Baghdad, bringing up to about 820 the number of U.S. forces working to bolster diplomatic security in Iraq.

Sotloff's mother, Shirley, appealed last Wednesday for her son's release in a videotaped message to Islamic State's self-proclaimed caliph, Abu Bakr al-Baghdadi.

In the video it released last month, Islamic State said Foley's death was in retaliation for U.S. air strikes on its insurgents who have overrun wide areas of northern Iraq.

The United States resumed air strikes in Iraq in August for the first time since the pullout of U.S. troops in 2011.

The raids followed major gains by Islamic State, which has declared an Islamic Caliphate in areas it controls in Syria and Iraq.

"We have seen a video that purports to be the murder of U.S. citizen Steven Sotloff by the Islamic State of Iraq and the Levant," White House National Security Council spokeswoman Bernadette Meehan said in a statement.

"The intelligence community is working as quickly as possible to determine its authenticity. If genuine, we are appalled by the brutal murder of an innocent American journalist and we express our deepest condolences to his family and friends. We will provide more information when it is available."


'SAVAGE KILLING'

Iraq's outgoing foreign minister, Hoshiyar Zebari, condemned what he called "this savage killing ... an example of savagery and evil," and said it was evidence of the need for Iraq and the West to defeat Islamic State.