By Alastair Macdonald and Guy Faulconbridge
BRUSSELS/LONDON (Reuters) - British Prime Minister Theresa May met European Union chief executive Jean-Claude Juncker before dawn in Brussels on Friday after a night flight from London, apparently having clinched a deal to open talks on post-Brexit trade
Neither answered when asked if a deal was done as they shook hands after May arrived at the European Commission's building but shortly afterwards Juncker's chief-of-staff tweeted a picture of white smoke emerging from a Vatican chimney - an indication that the European Union believes a deal is done.
May's key parliamentary ally in Northern Ireland said a text clarifying arrangements on the UK-EU border on the island of Ireland had been agreed, four days after 11th-hour objections from Belfast scuppered May's attempt to sign off on an accord over the Irish border during a lunch in Brussels on Monday.
The Commission said May and Juncker would brief reporters in the hour after their 7 a.m. (0600 GMT) breakfast meeting.
May would then meet European Council President Donald Tusk around 8 a.m. and hold a further news conference around 8:30 a.m. with the man who will chair a crunch summit next Friday where May hopes EU leaders will grant her trade negotiations.
EU and Irish officials had said earlier that Britain and Ireland were hours from agreement on a text outlining how they would run their post-Brexit land border on the island of Ireland, paving the way for a deal that would remove the last obstacle to opening free-trade talks with the European Union.
A carefully choreographed attempt to showcase the progress of Brexit talks collapsed at the last minute on Monday when the Northern Irish party that props up May's government vetoed a draft deal already agreed with the government in Dublin.
Since then, May has been scrambling to clinch a deal on the new UK-EU land border in Ireland that is acceptable to the EU, Dublin, her own lawmakers and Northern Ireland's Democratic Unionist Party (DUP), which keeps her government in power.
DUP leader Arlene Foster negotiated through the early hours with May, a DUP source told Reuters. Foster said a text was ready that removed her concerns that Northern Ireland would leave the EU on different terms from the rest of the United Kingdom. Dublin and the EU want "regulatory alignment" on both sides of the border after Brexit to avoid disrupting the peace.
Foster told Sky News: "We're pleased to see those change because for me it means there's no red line down the Irish Sea and we have the very clear confirmation that the entirety of the United Kingdom is leaving the European Union, leaving the single market, leaving the customs union."
"There are still matters there that we would have liked to have seen clarified, we ran out of time essentially, we think that we needed to go back again and talk about those matters but the prime minister has decided to go to Brussels in relation to this text and she says she has done that in the national interest."
Moving to talks about trade and a Brexit transition are crucial for the future of May's premiership, and to keep trade flowing between the world's biggest trading bloc and its sixth largest national economy after Britain leaves on March 30, 2019.
But the EU will only move to trade talks if there is enough progress on three key issues: the money Britain must pay to the EU; rights for EU citizens in Britain and British citizens in the EU; and how to avoid a hard border with Ireland.
The EU says May has an effective deadline of Sunday night if she wants to seal a deal and hope to have agreement on trade talks in time for the EU summit on Dec. 15.
All sides say they want to avoid a return to a hard border between EU member Ireland and the British-ruled province of Northern Ireland, which might upset the peace established after decades of violence.
The DUP insists that Northern Ireland, as part of the United Kingdom, must leave the EU in the same way as the rest of the United Kingdom.
To clinch a deal, though, May must ensure she has the support of the DUP, whose leader told her bluntly on Monday that it would not support her minority government's legislation unless the Irish border draft deal was changed.
She must also convince her divided Conservative Party that the deal she makes is acceptable.
(Reporting by Alastair Macdonald in BRUSSELS and Guy Faulconbridge in LONDON; Editing by Paul Tait)