Obama expected to speak to Cameron later today on Brexit

President Barack Obama has been briefed on the UK's referendum vote to leave the European Union and expects to have an opportunity to speak with British prime minister David Cameron later today, a White House official said.

The president, who is in San Francisco to attend a global entrepreneurship summit, would continue to be updated by his team on developments arising from the referendum “as the situation warrants,” the official said.

The result of the referendum will cause political earthquakes in Washington where administration officials were hoping for a vote to remain in the EU.

Mr Obama made a very public intervention in the Brexit debate when he urged British voters to support the UK's continued membership in the EU during a visit to London in April. He called the outcome of the referendum "a matter of deep interest to the United States because it affects our prospects as well." The UK would be "in the back of the queue" when it came to negotiating a trade deal with the US, Mr Obama said during his visit to the UK, warning that "it's not going to happen anytime soon."

Presumptive Republican presidential nominee Donald Trump, who flew out to Scotland from the US last night for the official opening of his golf resort in Turnberry today, backed Brexit, while his likely Democratic rival Hillary Clinton wanted the UK to stay in the EU.

The New York Times described the UK vote to leave the European Union as "a historic decision sure to reshape the nation's place in the world, rattle the continent and rock political establishments throughout the West."

The Washington Post reported that "British voters have defied the will of their leaders, foreign allies and much of the political establishment by opting to rupture this country's primary connection to Europe in a stunning result that will radiate economic and political uncertainty across the globe."

The Chicago Tribune said that "Britain voted to leave the European Union after a bitterly divisive referendum campaign, according to tallies of official results Friday, sending global markets plunging, casting British politics into disarray and shattering the stability of a project in continental unity designed half a century ago to prevent World War III."

Former US envoy to Northern Ireland, Richard Haass, president of the Council on Foreign Relations think tank, tweeted in response to the result that "pro-EU stances could fuel Sinn Féin push 4 vote for its stated goal of unity w Ireland. NI stability could be another casualty of Brexit."

Irish-American congressman Brendan Boyle, a Democrat from Pennsylvania, tweeted: "As a guarantor of the Good Friday Agreement, the US must strongly oppose any attempt to now reconstruct a hard border in N Ireland."

In a follow-up tweet, he wrote: "Now that England has dragged Scotland and N Ireland out of the EU, will they vote to leave the UK and remain in Europe?"