Arun Kumar| Washington| September 3, 2014 | 9.00 pm IST
The US has confirmed that the beheading video of a second American journalist was authentic, as President Barack Obama Wednesday vowed to punish the Islamic State terrorist group, saying America would not be intimidated.
"Those who make the mistake of harming Americans will learn that we will not forget... that our reach is long and that justice will be served," Obama said at a news conference in the Estonian capital Tallinn Wednesday.
"Our objective is clear. That is to degrade and destroy (IS) so that it's no longer a threat, not just to Iraq but also to the region and to the United States," he said, according to CNN.
"We can accomplish that. It's going to take some time, it's going to take some effort."
The terrorists who killed two American journalists, Steven Sotloff and James Foley, in a space of two weeks will be brought to justice as IS atrocities only served to galvanize American resolve to punish and dismantle the terror group, he said.
Earlier, in Washington, the White House National Security Council (NSC) confirmed the authenticity of the video showing the apparent beheading of Sotloff.
"The US Intelligence Community has analysed the recently released video showing US citizen Steven Sotloff and has reached the judgment that it is authentic," NSC spokesperson Caitlin Hayden said.
The terror group released a video Tuesday saying it was a "second message to America" against Obama's decision to conduct airstrikes against the IS in Iraq.
Sotloff, a 31-year-old Florida-based freelance journalist, who had gone missing in northern Syria over a year ago, was executed two weeks to the day after the beheading of American photo journalist James Foley.
Obama, who was speaking at a news conference on the eve of a NATO summit meeting in Wales, also addressed his much-criticiced statement last week that he has no strategy on the IS.
He said he was referring to a military strategy in Syria that "might" require congressional approval, CNN reported.
The world needs a regional strategy to defeat the group, he said.
"We've been putting together a strategy that was designed to do a number of things... What we have to make sure is we have a regional strategy in place."
"You wouldn't expect me to discuss various options that we will be considering," he said.
"But I can assure you that we will look at every possible option to protect this person."
"Whatever these murderers think they will achieve by killing innocent Americans like Steven, they have already failed," Obama said.
"We will not be intimidated," the president said.
"Their horrific acts only unite us as a country and stiffen our resolve to take the fight against these terrorists."
Confronting the IS is not on the formal agenda for the NATO meeting, but it is very much an issue expected to be addressed on the sidelines, the New York Times said