The European Union wants a quickie divorce, but Britain wants time to think things over.
Senior EU politicians demanded on Saturday the UK quickly cut its ties with the 28-nation bloc - a process Britain says won't begin for several months - as the political and economic shockwaves from the UK's vote to leave reverberated around the world.
"There is a certain urgency ... so that we don't have a period of uncertainty, with financial consequences, political consequences," French Foreign Minister Jean-Marc Ayrault said at a meeting in Berlin of the EU's six founding nations.
EU Commission chief Jean-Claude Juncker warned the split was "not an amicable divorce" but noted it was never "a tight love affair anyway."
Britons voted 52 to 48 per cent on Thursday in favour of ending their country's 43-year membership in the 28-nation bloc.
But no country has ever left the EU before, so no one knows exactly how the process will play out. Britain must, at some point, unambiguously notify the bloc of its intentions and set a two-year clock ticking for negotiating its departure. Until then, Britain remains an EU member.
In contrast to the clamouring of EU officials, the leaders of Britain's leave campaign, who had reassured voters that the EU would offer Britain good terms for a new relationship, were largely silent on Saturday.
England's 300-year-old union with Scotland could be another casualty of the referendum, since most people in Scotland voted to remain in the EU but were outvoted by a majority in much-larger England.
Scottish leader Nicola Sturgeon said her semi-autonomous administration would seek immediate talks with EU nations and institutions to ensure that Scotland could remain in the bloc.
"(We will) explore possible options to protect Scotland's place in the EU," she said after meeting with her cabinet in Edinburgh, adding that a new referendum on Scottish independence is "very much on the table."
Scotland voted in 2014 to remain a part of the UK, but that decision was seen as being conditional on the UK staying in the EU.
The victorious leave campaigners have said there's no rush to trigger Article 50 of the EU's Lisbon Treaty, which will begin a two-year exit process to renegotiate trade, business and political links between the UK and what will become a 27-nation bloc.
British Prime Minister David Cameron announced his resignation on Friday and said his successor, to be chosen by October, should be the one to navigate the tricky process of withdrawing from the bloc.
The favourite to succeed him, former London Mayor Boris Johnson, has said there's "no need for haste" - but EU leaders are saying the opposite, in insistent tones.
Juncker said the British had voted to leave and "it doesn't make any sense to wait until October to try and negotiate the terms of their departure."
"I would like to get started immediately," he said.
French Economy Minister Emmanuel Macron expressed the frustrations that many EU politicians feel, accusing Britain of taking the EU "hostage" with a referendum called to solve a domestic political problem: challenges to Cameron from right wing eurosceptics.
"The failure of the British government" has opened up "the possibility of the crumbling of Europe," Macron said at a debate in Paris.
Top diplomats from the European Union's six founding nations - France, Germany, Italy, the Netherlands, Belgium and Luxembourg - met in Berlin for hastily arranged talks and stressed that the exit process should be speedy.
"There must be clarity," Luxembourg Foreign Minister Jean Asselborn told reporters. "The people have spoken and we need to implement this decision."
France's Ayrault suggested Britain could name a new prime minister within "several days" - but that is likely instead to take several months. The process calls for Conservative MPs to winnow candidates down to two choices who will then be voted on in a postal ballot of party members.
Legally, there is little the EU can do to force Britain's hand, since Article 50 must be triggered by the country that is leaving. But political pressure and economic instability may force British politicians to act more quickly than they had hoped.
German Chancellor Angela Merkel struck a conciliatory note, saying it "shouldn't take forever" for Britain to deliver its formal notification of leaving.
Britain will remain an EU member until the divorce is finalised, but its influence inside the bloc is already waning. Leaders of the bloc will hold a summit in Brussels next week, and the second day, Wednesday, will take place for the first time without Britain.
