The United States is building an international coalition to combat the radical Sunni Muslim group.
The move comes at a time when a number of Australian citizens have been accused of fighting overseas for the Islamic State group.
Power said she would leave it to individual nations to announce their participation themselves.
Abu Eesa Niamatullah, a director of Prophetic Guidance in Manchester, said Henning's would-be killers are "defacing the religion of Islam."
In Berlin, politicians and non-Muslims joined about a thousand faithful to protest against the radical Islamists.
ISIS released a documentary-style video all but inviting U.S. troops back to Iraq for a fight.
Many news organizations have become increasingly reliant on freelance reporters to document conflicts around the world.
ISIS bombings in Baghdad Thursday and Friday suggest the militant Islamic State group has made new advances on the ground.
Of the three bombings in and around Baghdad Friday, one took place just minutes from the Green Zone.
France became the first country to assist the U.S. with airstrikes against the Sunni militant group in Iraq.
Militants fired mortar rounds, detonated car bombs and sent suicide bombers to liberate over 1,000 prisoners.
The video purportedly shows British journalist John Cantlie promising to reveal "the truth" about the group.
A senior member of the Islamic State militant group reportedly exhorted supporters in Australia to conduct public beheadings at random.
The Obama administration is adamant the battle against ISIS will not involve U.S. combat troops. What it will take to beat the militants.
The assertion that "U.S. troops will not have a combat mission” lands a day after a general seemed to suggest we may one day see the opposite.
Last week, U.S. Secretary of State John Kerry had called on Russia to help the U.S. counter the rise of the Islamic State.
A new 52-second-long propaganda video was released late Tuesday by the Al Hayat Media Center, the Islamic State's media arm.
Obama has ruled out "boots on the ground" as part of the campaign to wipe out ISIS, but the nation's top general said that could change.
A Taliban suicide bomber reportedly drove a vehicle loaded with explosives into a convoy carrying NATO-led troops.
Al Qaeda in the Arabian Peninsula is taking advantage of chaos in Yemen; U.S. drones and special forces failed to stop it.
Al Qaeda dismissed as "lies" a U.S. assessment that it is in decline, but a defiant online message issued by the network on Sunday made no mention of the ultra-hardline Islamic State group widely seen as its rival for the leadership of global jihad.
Iraqi President Fouad Massoum has expressed reservations about the involvement of Egypt, UAE and Saudi Arabia in airstrikes.