Western allies have pledged an increasingly aggressive campaign against Islamic State militants after the group executed a British aid worker in Syria.
IS militants on September 13 released video showing the beheading of David Haines, saying his execution was retribution for British arms shipments to Kurdish Peshmerga fighters who are battling the militants in northern Iraq.
The British Foreign Office said on September 14 that the video appears to be genuine.
British Prime Minister David Cameron condemned Haines' murder as “an act of pure evil” and vowed Britain will do all it can to catch the killers.
Cameron was chairing a meeting on September 14 of the government’s emergency response team, which includes the country’s top military and security chiefs.
That meeting was expected to focus on growing calls for Britain’s military to join a planned assault against the militants announced last week by U.S. President Barack Obama.
Australian Prime Minister Tony Abbott said on September 14 that his country is preparing to send 600 soldiers and 10 military aircraft to join the international coalition -- which includes the United States, most NATO members, and 10 Gulf Arab states.
Abbott denounced the IS militants as a “death cult.”
The French presidency said on September 14 that Haines’ murder demonstrates “why the international community must mobilize against” the group.
France is hosting a September 15 conference in Paris that will bring together coalition members for talks on determining what roles different countries will have in the campaign.
U.S. Secretary of State John Kerry says the strategy for confronting Islamic State militants is “coming together” as the international coalition is being built.
Kerry told the CBS television program “Face The Nation” that he is “extremely encouraged” by pledges of military assistance, and that some countries had offered ground troops.
But he said Washington would not coordinate its air strikes with Syrian government forces.
Kerry’s comments, broadcast by the CBS television program "Face The Nation" on September 14, were recorded in Cairo on September 13 shortly before Islamic State militants released the video of Haines' murder.
The Associated Press reports that Turkey has told NATO allies it will stay quietly behind the scenes, keeping its soldiers out of combat operations and refusing to allow NATO to use Turkish bases or territories to launch air strikes.
Turkey’s position is complicated by its opposition to Syrian President Bashar al-Assad’s regime, the capture by Islamic State militants of dozens of Turkish hostages, including diplomats, and Ankara’s wariness of bolstering Turkey’s rebellious Kurdish minority in the battle against the militants.
Kerry and U.S. Secretary of Defense Chuck Hagel were both in Ankara last week to press Turkey on its role after Turkey refused to sign a joint statement with Arab Gulf states condemning the Islamic State group and vowing to fight against it.
Obama said in a statement Washington will work with London and the broader coalition of nations to bring to justice those who killed Haines.
The attacker -- who appears to be the same man who beheaded two U.S. journalists in earlier videos -- said Britain’s alliance with the United States will "accelerate your destruction" and will drag the British people into "another bloody and unwinnable war."
At the end of the video, the killer also threatened to execute another captive -- identified in a caption by name as another British citizen.