Senior officials from 21 countries are gathering in London to discuss efforts to tackle the militant group Islamic State (IS) in Syria and Iraq.
Those taking part in the one-day conference include US Secretary of State John Kerry and Iraqi Prime Minister Haider al-Abadi.
They will discuss how to halt the flow of recruits to IS and stop its funds.
They will also look at providing more military help to those fighting IS on the ground, and more humanitarian aid.
BBC diplomatic correspondent James Robbins says ministers will be exploring ways to accelerate and intensify a long-term campaign.
Recent attacks by Islamic militants in France have put even greater political pressure on governments to show decisive results, he adds.
Mr Kerry, who will co-host the talks with UK Foreign Secretary Philip Hammond, said there was “greater determination” than ever to defeat IS.
“Terrorists want to drive us apart, but in fact their actions have had the opposite effect, they’re bringing us together,” he told reporters before leaving for London.
