LONDON: British Prime Minister Boris Johnson played down hopes of a breakthrough in his last-ditch bid to strike an amicable divorce deal with the European Union.
Negotiators went behind closed doors for intensive talks in Brussels after Johnson outlined a new set of proposals to Irish Prime Minister Leo Varadkar on Thursday.
They have very little time left to succeed.
EU leaders will meet on Thursday and Friday for a summit held under the pressures of the Oct 31 Brexit deadline just two weeks away.
The 27 would ideally like to have a full proposal to vote on by then.
But the sides are trying to achieve in a few days what they had failed to in the more than three years since Britons first voted to leave the European Union after nearly 50 years.
German Chancellor Angela Merkel will discuss the available options with French President Emmanuel Macron late Sunday.
European officials said the bloc's Brexit negotiator Michel Barnier will also brief EU ambassadors on the state of play on Sunday evening.
Downing Street said Johnson told his cabinet to brace for a cliff-hanger finish in the coming days.
Johnson reiterated "that a pathway to a deal could be seen but that there is still a significant amount of work to get there and we must remain prepared to leave on October 31," a Downing Street spokesman said.
Outgoing EU chief Jean-Claude Juncker said British politics were getting more difficult to decipher than the riddle of an "Egyptian sphinx".
"If the British ask for more time, which they would probably will not, it would in my view be a historical nonsense to refuse them," Juncker told Austria's Kurier newspaper.
Johnson rose to power in July on a promise not to extend Brexit for a third time - even for a few weeks.
Breaking that pledge could come back to haunt him in an early general election that most predict for the coming months.
Johnson is under parliamentary orders to seek a extension until Jan 31 of next year if no deal emerges by Saturday.
He has promised to both follow the law and get Britain out by Oct 31 - a contradiction that might end up being settled in court.
Ireland's Varadkar hinted on Thursday that he could support the talks running on up to the Oct 31 deadline if a deal seemed within reach.
The few details that have leaked out suggest a compromise around the contentious Irish border issue Britain's Northern Ireland partially aligned with EU customs rules.
Whether such a fudge suits both Brussels and the more ardent Brexit backers in parliament who must still approve a deal should become clearer by the end of the week.
Britain will only avoid a chaotic breakup with its closest trading partners if the agreement is also passed by the UK parliament - something it has failed to do three times.
Johnson heads a minority government and must rely on the full backing of not only his own fractured Conservatives but also Northern Ireland's small Democratic Unionist Party.
DUP's parliamentary leader Nigel Dodds warned Johnson that "Northern Ireland must remain entirely in the customs union of the United Kingdom" and not the EU.
"And Boris Johnson knows it very well," Dodds told Italy's La Repubblica newspaper.
The comments do not necessarily rule out DUP support.
UK media are presenting Johnson's mooted compromise as a "double customs" plan that could be interpreted to mean that Northern Ireland is leaving EU rules.
Yet details are still under discussion and the prime minister's allies are urging lawmakers to give the British leader a chance.
Main opposition Labour Party leader Jeremy Corbyn signalled on Sunday that he would wait for the outcome of the EU summit before trying to force an early election.
But he added that there there was "a strong possibility" that those polls would come before the Christmas break.