President Barack Obama, who had warned against Britain quitting the European Union, said Friday that Washington would respect the British voters' decision to do just that.
The US leader said Britain and the European Union would both remain "indispensable partners" of the United States and that the "special relationship" with London would endure.
"The people of the United Kingdom have spoken, and we respect their decision," Obama said, in a statement from his White House office.
But, in a nod to Washington's frustration that its ally has been unwilling to back a European project seen as a cornerstone of Western power, Obama also paid tribute to the EU.
"The special relationship between the United States and the United Kingdom is enduring, and the United Kingdom's membership in NATO remains a vital cornerstone of US foreign, security, and economic policy," he said.
"So too is our relationship with the European Union, which has done so much to promote stability, stimulate economic growth, and foster the spread of democratic values and ideals across the continent and beyond," he said.
"The United Kingdom and the European Union will remain indispensable partners of the United States even as they begin negotiating their ongoing relationship to ensure continued stability, security, and prosperity for Europe, Great Britain and Northern Ireland, and the world."