US 'will not be intimidated' by IS
President Barack Obama has that the United States will not be intimidated by Islamic State (IS) militants after the beheading of a second American journalist.
He also vowed the US will build a coalition to "degrade and destroy" the group but still did not give a timeline for deciding on a strategy to go after the extremist group's operations in Syria.
"It'll take time to roll them back," the president said at a news conference during a visit to Europe.
Mr Obama's comments came after he said the US had verified the authenticity of a video released yesterday showing the beheading of freelance reporter Steven Sotloff, two weeks after journalist James Foley was similarly killed.
The president vowed the US would not forget the "terrible crime against these two fine young men". He added: "Our reach is long and justice will be served."
In the latest video, a masked militant warns Mr Obama that as long as US airstrikes against the militant group continue, "our knife will continue to strike the necks of your people".
Mr Obama responded that he will continue to fight the militant threat and the "barbaric and ultimately empty vision" it represents.
"Our objective is to make sure that Isil (Islamic State) is not an ongoing threat to the region," he said. "And we can accomplish that. It's going to take some time and it's going to take some effort."
Mr Sotloff, a 31-year-old from the Miami, Florida, area who freelanced for Time and Foreign Policy magazines, vanished a year ago in Syria and was not seen again until he appeared in the video that showed Mr Foley's beheading.
Dressed in an orange jumpsuit against an arid Syrian landscape, Mr Sotloff was threatened in that video with death unless the US stopped airstrikes on IS.
In the video distributed yesterday and titled A Second Message to America, Mr Sotloff appears in a similar jumpsuit before he is apparently beheaded by a fighter with IS, the extremist group that has conquered wide swaths of territory across Syria and Iraq and declared itself a caliphate.
British Foreign Secretary Philip Hammond said that the masked, British-accented jihadist appears to be the same person shown in the footage of Mr Foley.
In the video, the organisation threatens to kill another hostage, this one identified as a British citizen.
Last week, Mr Sotloff's mother, Shirley Sotloff, pleaded with his captors for mercy, saying in a video that her son was "an innocent journalist" and "an honourable man" who "has always tried to help the weak".
Mr Obama said the prayers of the American people are with the family of the "devoted and courageous journalist" who deeply loved the Islamic world and whose "life stood in stark contrast to those who murdered him so brutally".
"Whatever these murderers think they will achieve by murdering innocents like Steven, they have already failed," Mr Obama said. "We will not be intimated. Their horrific acts only unite us."