President Barack Obama vowed Wednesday that the United States would not be intimidated by the beheading of a second American reporter but acknowledged the fight against the jihadists would take time.
Obama pledged that justice would be done to the Islamic State (IS) killers of 31-year-old reporter Steven Sotloff, wherever they hid and however long it took. Sotloff was a dual Israel-US citizen and had even studied in Israel, it emerged Wednesday, the day after a video of his brutal murder was aired online.
"The bottom line is this, our objective is clear and that is to degrade and destroy (Islamic State) so that it's no longer a threat not just to Iraq but also the region and to the United States," Obama told a news conference.
"Whatever these murderers think they will achieve with killing innocent Americans like Steven, they have already failed," Obama said. "They failed because, like people around the world, Americans are repulsed by their barbarism. We will not be intimidated."
Sotloff moved to Israel in 2005 and studied at the Interdisciplinary Center Herzliya (IDC). After his capture in Syria, it seems any connection to Israel was deleted from his online presence in a bid to prevent the information from reaching his captors. Ynet spoke to one of his editors who described him as one of the most "courageous journalist" she knew.
Obama warned that eliminating the threat posed to the region by the group from its bases in Iraq and Syria would take time.
IS said the journalist's killing, which comes on the heels of the beheading last month of another US reporter, James Foley, was in retaliation for expanded US air strikes against its fighters in Iraq over the past week. It warned a British hostage would be next unless London backs off from its support for Washington's air campaign.
Obama said "Those who make the mistake of harming Americans will learn that we will not forget and that our reach is long and that justice will be served.".
Obama said Washington was determined to halt the IS threat to the region but warned it would depend on close cooperation with partners in the region.
He has previously admitted that his administration has yet to develop a comprehensive strategy for tackling IS on both sides of the Iraq-Syria border.
Washington has ruled out any air strikes for now against IS fighters on the Syrian side, where they hold a large swathe of the east.
Obama has also ruled out any cooperation with the Damascus regime against IS, for fear that it would drive other Sunni rebel groups in Syria into alliance with the jihadists.
British Prime Minister David Cameron said the video depicted an "absolutely disgusting, despicable act" and convened a meeting of security chiefs to discuss how to tackle the IS threat.
The masked executioner in the video spoke with a London accent and claimed to be the same man, confirmed by UK security services as a Briton, who beheaded Foley.
"I'm back, Obama, and I'm back because of your arrogant foreign policy towards the Islamic State," the black-clad jihadist says, wielding a combat knife.
"So just as your missiles continue to strike the necks of our people, our knife will continue to strike the necks of your people," he declares, before reaching round to cut his captive's throat.
The militant condemns US air strikes against IS fighters around both Mosul Dam in the north and the Shiite Turkmen town of Amerli further south, which dates the video to the past week.
At the end of the five-minute video recording, the militant threatens another captive, identified as Briton David Cawthorne Haines.
"We take this opportunity to warn those governments that enter this evil alliance of America against the Islamic State to back off and leave our people alone," he says.
Britain has maintained a media silence about the kidnapping of aid worker Cawthorne Haines and there were few immediate details about when or how he was abducted.
Britain has not carried out any air strikes of its own against jihadist targets in Iraq but it has made extensive reconnaissance flights in support of the US air campaign from its base in Cyprus.
In a statement, the Sotloff family, who live in Miami, said: "The family knows of this horrific tragedy and is grieving privately. There will be no public comment from the family during this difficult time."
After Foley's death, Sotloff's mother Shirley had addressed a video message to IS leader Abu Bakr al-Baghdadi pleading for her son's life, and insisting he had no influence on US policy.
'Brave and talented'
Sotloff's former employers at Time and Foreign Policy paid tribute to a man widely respected for his intrepid reporting in Syria and the wider region, including a previous stint in Libya.
UN Secretary General Ban Ki-moon said the world was outraged at the apparent beheading.
"I strongly condemn all such despicable crimes and I refuse to accept that whole communities can be threatened by atrocities because of who they are or what they believe," Ban said.
Hours after the posting of the video, the White House announced that Obama had authorized about 350 more US troops to beef up security at US diplomatic facilities and protect personnel in Baghdad.
Washington initially limited the air support it launched on August 8 to Iraqi Kurdish forces fighting the jihadists in the north.
But late last week it expanded it to Iraqi troops and Shiite militia battling to relieve trapped civilians in Amerli, helping them to break the months-long IS siege on Sunday.
Assistance is now arriving in the town, brought in both by Shiite militia fighters and the United Nations.