LONDON (AP) — British and European Union negotiators were meeting Friday in search of an elusive Brexit deal, as Ireland's deputy leader warned that the two sides remain far apart despite an improvement in the "mood music."

Britain's Brexit Secretary, Stephen Barclay, was holding talks in Brussels with EU chief negotiator Michel Barnier, as the U.K. and the EU explore whether they can strike a last-minute deal before Britain's scheduled departure date of Oct. 31.

After months of stalemate, the two sides have begun to sound slightly more optimistic. European Commission President Jean-Claude Juncker told Sky News on Thursday that "we can have a deal," though he wouldn't say whether the odds of getting an agreement were better than 50-50.

Irish Deputy Prime Minister Simon Coveney told the BBC on Friday that there were still "serious problems" over how to handle the Irish border issue once Britain leaves the EU.

He said British Prime Minister Boris Johnson had convinced Irish leaders he is serious about seeking a new deal, but had not provided realistic alternatives to the "backstop," a contentious measure for maintaining an open Irish border.

Johnson insists he is working hard to get an agreement with the EU that will ensure a smooth departure. EU leaders are skeptical of that claim, saying the U.K. has not produced any concrete proposals.

"We are still waiting for serious proposals from the British government," Coveney said.

Britain says it has not revealed detailed proposals because they would likely leak, to the detriment of negotiations. But the government insisted Thursday it had sent "confidential technical non-papers which reflect the ideas the U.K. has been putting forward." Non-papers are documents intended for discussion, rather than formal proposals.

The EU confirmed it had received new documents from Britain relating to ways of maintaining an open border between EU member Ireland and the U.K.'s Northern Ireland — the key sticking point to a deal. An invisible border is vital both to the local economy and to Northern Ireland's peace process.

Brexit supporters oppose the backstop because it potentially keeps the whole of the U.K. bound to EU trade rules, limiting its ability to forge new free trade agreements around the world after its departure.

Britain has suggested the backstop could be replaced by "alternative arrangements" — a mix of technology to replace border checks and a common area for agricultural products and animals covering the whole island of Ireland.

"We want to find a solution, we want to get a deal, and we want to allow the U.K. to leave the EU in an orderly and sensible manner, but we cannot allow Ireland to be the collateral damage of that," Coveney said.

Gregory Katz in London contributed to this story.

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