n the first reaction by a senior U.S. official, Vice President Joe Biden said on Friday the United States would rather Britain had voted to remain in the European Union, but respected the result of the Brexit referendum.

"I must say we had looked for a different outcome. We would have preferred a different outcome ... but the United States has a long-standing friendship with the United Kingdom and that very special bond will endure,” he said in a speech in Dublin.

"We fully respect the decision they have made," he said.

Britain's decision to leave the EU has forced the resignation of Prime Minister David Cameron and has dealt the biggest blow to the European project of greater unity since World War Two.

U.S. President Barack Obama, who was briefed by his advisers on Britain's vote, had argued passionately against Brexit during an April visit to London.

Obama had traveled to London at the request of Cameron, whom he calls a friend, exhorting Britons to stay in the EU. The unusual intervention was denounced as meddling by those campaigning for the country to leave the EU.

Obama said that his involvement had been justified because of the two countries' longstanding special relationship.

Obama also warned that leaving the EU would put Britain at the "back of the queue" for a trade deal with the United States.

Obama's term in the White House ends in January 2017. His former Secretary of State Hillary Clinton, the presumptive Democratic candidate in the Nov. 8 election, had also said she hoped the UK would stay in the EU.

The presumptive Republican nominee - real estate magnate Donald Trump - had taken the opposite stance, saying he thought the UK should leave.

Trump, in Scotland on Friday to reopen a golf resort, told reporters that Britons "took back control of their country" by voting to leave the European Union.

He added that "what happened should have happened" and Britain would be stronger for it.

House Speaker Paul Ryan said he respected the decision made by the people of the United Kingdom and that the "special relationship" would be unaffected by the vote.