The UK will continue bombing Islamic State targets for "as long as it takes", Philip Hammond tells the United Nations as he urged leaders to unite to "crush" the extremist group.
The Foreign Secretary told the UN General Assembly in New York on Wednesday that the people of Syria were facing the "twin evils" of IS and Bashar Assad's "murderous regime".
He urged leaders to work together to "banish" IS, also known as ISIL, and "its ideology from the face of the earth".
Mr Hammond said the chaos in Iraq and Syria - the "crucible of human civilisation" - was where "our collective values and our will to act are being most immediately challenged".
He praised the "extraordinary generosity" of Turkey, Lebanon and Jordan for their humanitarian efforts taking in Syrian refugees and said it is important to "support them as they bear that burden".
On Tuesday, Hammond defended a decision to add four Britons, thought to be home-grown terrorists, to a UN sanctions list.