The United States has launched a new barrage of airstrikes against the Islamic State, the extremist group that beheaded American journalist James Foley and has seized a swathe of territory across Iraq and Syria.
President Barack Obama vowed relentless pursuit of the terrorists, and the White House revealed that the U.S. had launched a secret rescue mission inside Syria earlier this summer that failed to rescue Foley and other Americans still being held hostage.
In brief but forceful remarks, Obama said the U.S. would "do what we must to protect our people," but he stopped short of promising to follow the Islamic State to its safe haven within Syria, where officials said Foley had been killed.
Later, though, the administration revealed that several dozen special operations troops had been on the ground in Syria briefly in an effort to rescue the hostages, but did not find them.
And looking forward, the State Department refused to rule out future U.S. military operations in Syria, where Obama has long resisted intervening in a three-year civil war.
Western nations agreed to speed help to combat the militants - most notably Germany, which bucked public opposition by announcing it would arm Iraqi Kurdish fighters to battle the Islamic State.
French Foreign Minister Laurent Fabius said he was outraged by the beheading, deeming it evidence of a "caliphate of barbarism." Italy's defense minister said the country hopes to contribute machine guns, ammunition and anti-tank rockets.
The Islamic State called Foley's death a revenge killing for U.S. airstrikes against militants in Iraq, and said other hostages would be slain if the attacks continued. Undeterred, the U.S. conducted 14 additional strikes after a video of the beheading surfaced, bringing to 84 the total number of airstrikes since they began on August 8.
Two U.S. officials said additional American troops - probably less than 300 - could be headed to Iraq to provide extra security around Baghdad, where the U.S. Embassy is located.
That would bring the total number of American forces in Iraq to well over 1,000, although officials said no final decision had been made.
Foley's mother said she is praying for other hostages being held by the Sunni-dominated terror group, and described her son's slaying as "just evil."
"No just God would stand for what they did yesterday, and for what they do every single day," the president said. The Islamic State militants have promised to eliminate all people they consider heretics in their quest to create an extremist state across much of Iraq and Syria.
"We will be vigilant and we will be relentless," Obama said, urging unity among Mideast governments in order to eviscerate the extremist group's growing power.
In capitals across the Middle East, news of Foley's death was met largely with silence, including Syria and Iraq - the two countries where the Islamic State is strongest.