The contribution will facilitate the return of Syrian refugees and try to ensure militant groups cannot “re-emerge” to threaten Syria or plan attacks against the international community, the official Saudi Press Agency has said.

It explained: “The funds will focus on projects to restore livelihoods and essential services in the areas of health, agriculture, electricity, water, education, transportation (key roads and bridges), and rubble removal.”

The US State Department said in a statement: “This significant contribution is critical to stabilisation and early recovery efforts and comes at an important time in the campaign.”

It added that the territory of the Islamic State is down to 400 square miles in Syria and nearly 150,000 people have returned to the city of Raqqa.

The statement also called on the US’s partners and allies “to do their share in this effort”.

This comes as Donald Trump’s administration looks to cut back on foreign aid, including funds for programmes in Syria, the West Bank and Gaza.