A US commander in Pacific East Asia warned that 1000 militants from the region were seeking to join the movement, and this week an Algerian off-shoot group killed a French hostage.
But 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 the British Parliament votes to take part, the Royal Air Force will join jets from the US, France, Saudi Arabia, the United Arab Emirates, Bahrain and Jordan hitting Isis targets.
And the allies' domestic intelligence services are also stepping up their game.
The FBI says it has identified a militant with a British accent seen executing Western hostages in Isis videos.
And in London, police arrested nine people suspected of links to radical extremism, including a notorious radical preacher.
The latest wave of strikes hit the small-scale crude refineries that Isis gangs use to generate up to US$2 million ($2.5 million) in revenues a day.
The strikes by US and Arab warplanes against the oil refineries killed 14 jihadists but also left five civilians dead, including a child, according to the Britain-based monitoring group the Syrian Observatory For Human Rights.
The Pentagon says it is aware of reports of civilian casualties, and is investigating, but insists raids are carried out with precision.
A spokesman said foreigners from Europe, Arab nations, Chechnya and Turkey made up the vast majority of the more than 140 jihadists killed since the US-led raids began in Syria earlier this week.
Also at the General Assembly, Iranian President Hassan Rouhani said the West was responsible for "strategic blunders" that had created terror havens, but also called for action against jihadists.
Rouhani said western governments were responsible for sowing the seeds of the outbreak of extremism that has brought turmoil to the Middle East and demanded that they "acknowledge their errors" and apologise.
"Certain intelligence agencies have put blades in the hand of madmen, who now spare no one," Rouhani said.
"Currently our peoples are paying the price. Today's anti-Westernism is the offspring of yesterday's colonialism. Today's anti-Westernism is a reaction to yesterday's racism.
"The strategic blunders of the West in the Middle-East, Central Asia, and the Caucuses have turned these parts of the world into a haven for terrorists and extremists.
"Military aggression against Afghanistan and Iraq and improper interference in the developments in Syria are clear examples of this erroneous strategic approach in the Middle East."
Isis has committed widespread atrocities including mass executions of captured Iraqi soldiers, forced conversions of non-Muslims and the on-camera beheadings of Western hostages.
- AFP, Independent