The Pentagon said Arab allies assisted overnight strikes in Syria. Islamic State bases were the main target, but the US said it also struck at a separate al-Qaeda affiliate suspected of plotting terror attacks on Western targets.
The video's release appears timed as a response to Gen. Martin Dempsey's testimony Tuesday to a Senate committee. He raised the possibility of sending US troops to fight Islamist militants in Iraq and Syria.
The Obama administration said it would destroy Syria's air defenses if they fire on US planes attacking Islamic State militants inside Syria. The White House says it won't coordinate airstrikes with Damascus.
If US statements are taken at face value, Obama has set the country a mammoth task in the Middle East with a very low probability of success.
The US Secretary of State received promises of help in Obama's new war against the Islamic State group yesterday from 10 Arab states.
So far, it doesn't look like much. That explains why the US president was short on specifics when he vowed to take the fight to the jihadis.
President Obama said Wednesday that the US would take the fight to Syria as part of an international coalition to destroy the self-declared Islamic State. But he ruled out a combat role for US troops.
Pledges are rolling in for a NATO 'rapid reaction' force, a direct response to what members say is Russian aggression against non-NATO member Ukraine.
The self-declared Islamic State has released a video showing the beheading of a second US journalist. The US has few easy options to navigate a complex, multi-front war in Iraq and Syria.
Videotaped atrocities in an attempt to spread fear are nothing new for IS. But it appears to be stepping up its propaganda as world powers start to engage in halting its spread.
Midwesterner Douglas McCain was killed over the weekend. His radicalization fits a pattern of foreigners who fight for militant groups.
Islamic State militants had demanded millions of dollars for James Foley's release. While the US government refuses to pay ransoms to kidnappers, some European governments have done so in the past, enriching Al Qaeda and its affiliates.