British lawmakers are expected to vote on Friday to join the international air strikes against Islamic State fighters, as the United States and its Arab allies turn up the heat on the jihadists.
In Washington yesterday, the Pentagon released cockpit video of guided missiles from F-15 jets smashing into oil refineries and Islamic State compounds in the latest night of strikes in Syria.
US President Barack Obama took advantage of the UN General Assembly in New York this week to bend the ears of fellow world leaders over the threat posed by the jihadists.
The group has seized a large tract of territory spanning eastern Syria and northwestern Iraq, and has begun to make headway inspiring Islamists further afield to pledge fealty to its "caliphate".
British lawmakers will vote today on whether to bomb Islamic State militants in Iraq, though not in Syria.
"We are facing an evil against which the whole world must unite. And, as ever in the cause of freedom, democracy and justice, Britain will play its part," Prime Minister David Cameron told a United Nations summit in New York, before flying home for the vote.
Cameron has asked Britain not to be "frozen with fear" about re-entering conflict in a country its last troops from the previous war left only in 2011.
French jets were in action again yesterday in the skies over Iraq.
The US-led coalition has also made progress in building a united front. Turkey has pledged stronger support for the campaign, and Obama spoke to President Recep Tayyip Erdogan yesterday.
If, as expected, the British parliament votes to take part, the Royal Air Force will join jets from the United States, France, Saudi Arabia, the United Arab Emirates, Bahrain and Jordan hitting IS targets.
Belgium and the Netherlands said they would each send six F-16 fighter bombers to take part in the air campaign in Iraq.
The Netherlands will also deploy 250 military personnel and 130 trainers for the Iraqi military, and Greece said it would send arms to Kurdish forces battling the jihadists.
In all more than 50 nations have joined the US-led coalition against IS, including key Arab states, and in recent days more countries have promised concrete military support. And the allies' domestic intelligence services are also stepping up their game. The FBI said it had identified a militant with a British accent seen executing Western hostages in IS videos.