Members of the coalition fighting Islamic State extremists in Syria and Iraq are due to meet for a summit in London on Thursday.
Foreign Secretary Philip Hammond and Secretary of State John Kerry are expected to host talks with ministers from about 20 countries, including the Arab states.
They will discuss the progress of the fight against Islamist militants who have taken control of territory in Iraq and Syria.
The meeting will take place at Lancaster House in central London, according to an official.
It comes as Prime Minister David Cameron gave an interview to the American network CBS in which he spoke about measures to tackle extremism at home.
Mr Cameron said Britain is facing a "very severe threat" from Islamist extremists, including so-called "lone wolf" terrorists.
"In Britain's history, we've had some very intense times of terrorist threats," he said.
"Certainly we face a very severe threat. That's what we're calling it: severe, because we believe an attack is highly likely.
"But frankly, we've been in this struggle against extremist, Islamist terrorism now for well over a decade and a half, so we know what it takes to win, but it's going to take a lot of perseverance."
He said the terror threat "keeps morphing" over time.
"This threat keeps morphing, because it's the same fundamental problem, extremist Islamist terror," he said.
"But whereas the majority of it was coming from the Afghanistan, Pakistan area, now you see more of it coming out of Iraq and Syria, and the threat posed by ISIL.
"Added to that, you've got the so‑called 'self‑starter' or 'lone wolf' terrorists, people who've been radicalised because of what they've seen on the internet who... may not be connected to some plot that is being hatched in Iraq or Syria.
"So the threat has changed and altered, but it's still based on the fundamental problem of a poisonous death cult narrative which is the perversion of one of the world's major religions.
"And that's the thing we're still up against."
Earlier Mr Cameron vowed to tackle what he called the "poisonous narrative of Islamist extremism that is turning too many young minds".
He was speaking following two days of talks with US President Barack Obama in Washington where they said a new group would be set up to exchange information and expertise to tackle the terror threat.
There are fears about the spread of terrorism after the Paris attacks that left 17 people dead and the arrest of more than two dozen people in anti-terror raids in Belgium, Germany and France.
On Saturday an 18-year-old woman who was arrested at Stansted airport on suspicion of terrorist offences was released on bail.
Anti-terror officers arrested the teenager when she arrived on a flight at around 4pm on Friday.
