"But at this stage it is very hard to make a prediction", said an official.
British Prime Minister Theresa May and the Irish government have failed to reach a deal on the crucial Brexit issue of the Northern Ireland border, authorities announced on Monday. But Ireland and the other EU nations are demanding to know how that will work if Britain is outside the EU's borderless single market and its tariff-free customs union, a looser trading bloc that includes non-EU states like Turkey.
Mrs May was forced to break off her working lunch with European Commission President Jean-Claude Juncker to hold crisis talks with DUP leader Arlene Foster after details of the deal came to light.
"Crucially it is clear that we want to move forward together, but on a couple of issues, differences do remain, which require further negotiation and consultation", said May before heading to meet President of the European Council Donald Tusk nearly one-hour late than scheduled.
If she had ignored their concerns, there's little doubt that the party's 10 MPs would have sat on their hands and not supported the Conservatives in important votes on the EU Withdrawal Bill this week.
Those words were meant to provide reassurance to the Irish government that, should the European Union and the United Kingdom not be able to reach a trade deal, there would be a backstop that would guarantee trade across the border would continue pretty much as it does now.
Earlier in the day, European Council President Donald Tusk tweeted that he was "encouraged" that sufficient progress was being made on the key Brexit issues, following a phone call with Irish Taoiseach Leo Varadkar.
"I accept that the Prime Minister (Theresa May) has asked for more time, and I know that she faces many challenges, and I acknowledge that she is negotiating in good faith", he added.
In London, May's spokesman said: "Progress is being made". And on numerous issues there is a common understanding.
May said that "on a couple of issues some differences do remain which require further negotiation and consultation".
"I hope we are in a place this evening where Irish people north and south will get reassurance from the wording that is very close to being finalised now".
It is understood this is a sticking point in reaching a deal on post-Brexit citizens' rights, the part of the phase one divorce negotiations that had previously been considered to be the most advanced.