WASHINGTON, August 22. /ITAR-TASS/. The Islamic State (IS) group “clearly poses a long-term threat”, US Defense Secretary Chuck Hagel said on Thursday. It is possible that IS militants will regroup and stage a new offensive, Hagel added.

"They are beyond just a terrorist group. They marry ideology, a sophistication of strategic and tactical military prowess, they are tremendously well-funded... this is beyond anything that we have seen," Hagel said.

Security concerns broadened as the Islamic State released a video on Tuesday, showing a purported beheading of journalist James Foley, who went missing in Syria in November 2012.