Deadlock over the Irish border means it is more likely that the UK will crash out of the European Union without a deal, the Taoiseach has warned.
Leaders from across the bloc are stepping up preparations for a no-deal scenario as the deadline looms for find a solution, Leo Varadkar said.
After talks in Guernsey with UK cabinet minister David Lidington and the first ministers of Scotland and Wales, the Taoiseach said efforts to find a resolution would intensify over the next couple of months.
He said: "I think it (no deal) is more likely than it was a few months ago but I still don't think it is likely.
He added: "That's what we are going to do over the next couple of months, really try to intensify our efforts to come to a withdrawal agreement," he said.
Brussels has warned that more work was needed on how to deal with the 300-mile border between Northern Ireland and the Republic, the UK's only land frontier with a European state, and protect frictionless movement after the withdrawal.
Both sides in the negotiations have agreed to include a so-called "backstop" option in any Brexit treaty, which would commit the UK to align with an EU regulatory framework in the absence of a wider trade deal.
But the shape of that fall-back remains a sticking point, with the EU rejecting a UK contention that it should only be temporary, even if a broader agreement fails to materialise.
Speaking after a meeting of the British-Irish Council, Mr Varadkar said there could only be a withdrawal agreement if there was a backstop for the Irish border in it.
"But it is also important to recognise that it is not something we ever want to have to use."
EU leaders will warn there has not been enough progress on the border issue when they gather for a summit in Brussels next week.
Mr Varadkar said: "All EU countries, as we will conclude and agree next week, will be stepping up our preparations for all possible scenarios and that does include a no-deal scenario.
"All countries will be preparing for that."
Guernsey's chief minister Gavin St Pier said it was wise and prudent to prepare for no deal but added it was "not necessarily with any expectation that that will be the outcome".
The BIC brings together representatives of the Irish and British governments, the devolved administrations in Northern Ireland, Scotland and Wales and the Isle of Man, Guernsey and Jersey crown dependencies.
Mr Lidington, the de facto deputy prime minister, said it was self-evidently in the interests of all countries to reach an agreement.
-PA & Digital Desk