The DUP has said further work is required on UK prime minister Boris Johnson's Brexit deal as gaps remain over what they can sign up to, following talks at Downing Street.
“We respect [the] fact negotiations are ongoing, therefore cannot give a detailed commentary, but it would be fair to indicate gaps remain and further work is required,” it said in a statement.
The Northern Irish party's remarks come as talks are ongoing in Brussels on a possible Brexit deal.
Taoiseach Leo Varadkar had earlier said progress was being made in the closed-door talks between the EU and UK, but that it was "unclear" if a new deal would be struck tonight.
However, he said he was yet to receive a “detailed” briefing from Brussels.
He said the gap was still “quite wide” between the EU and UK, particularly on the issue of customs arrangements on the island of Ireland.
“The initial indications are that we are making progress,” Mr Varadkar said. “The negotiations are moving in the right direction.”
But whether the progress is sufficient to allow for a revised Brexit deal to be presented to the European Council meeting this week is "as of now unclear", he added.
“We are just going to have to see how the next few days go. If we can get to an agreement on Thursday or Friday and if the House of Commons is able to vote in favour of that agreement on Saturday it may not be necessary to even consider an extension but it is too early to make that assessment at this stage.”
The Taoiseach also said his preference is still to hold an election in May 2020 and added that, unlike Fianna Fáil, he had not linked the survival of the Government to Brexit.
The prospects for a second EU summit this month continued to loom as the negotiating teams struggled to put legal language on a potential deal.
Failure to reach a deal by tonight will see leaders agreeing to reconvene a summit later in the month, either to ratify a deal should the talks produce one, or to discuss an extension.
In Luxembourg EU chief negotiator Michel Barnier and Tánaiste Simon Coveney were resolutely optimistic that a deal could still be done by this evening if the will was there.
“Difficult but possible,” Mr Barnier told journalists and then member states at their meeting of Brexit ministers.
It was “high time to turn good intentions into legal text,” he said. Speaking to journalists after the meeting Mr Coveney said he did not think “it’s inevitable” there would be no deal in time for a two-day leaders’ summit on Thursday.
Progress in the talks was “slow and they will need to make significant progress today,” he said, “ if there is to be a deal that Michel Barnier can report on tomorrow to EU capitals in advance of the leaders’ summit.”
Speaking after emerging from a briefing with Mr Barnier on Tuesday, the Tánaiste warned a lot of progress needs to be made over the next 24 hours between the EU and UK negotiating teams.
“I don’t think it’s inevitable that they can’t get a deal before the summit,” Mr Coveney said. “I think what Michel Barnier said today was very clear, that it’s difficult but possible to have a deal between the two negotiating teams this side of the leaders’ summit.
Mr Coveney emphasised that a legal text was required and said “there will not be negotiation of text at the summit. The EU is very clear on that. So if there is going to be a deal at the summit the task force and the British negotiating team have to finalise text.”
Mr Coveney acknowledged “it is of course possible to move beyond the summit and continue talks next week because the UK is not due to leave the EU before the end of the month but from everybody’s perspective if we cloud bring clarity at this summit that would be a welcome development.”
Mr Coveney would not be drawn on the substance of the talks but diplomats in Brussels say that, encouraged by Mr Barnier, in broad outline it is being welcomed by member states as the basis of agreement.
However, some scepticism remains about the mechanics of the UK’s proposed customs controls.
Speaking to BBC Northern Ireland, DUP leader Arlene Foster said it was important that the North remain in the UK customs union in any Brexit deal.
"We want to get a deal but it has to be a deal that respects the economic and constitutional integrity of the United Kingdom and that means all of the United Kingdom, Northern Ireland included
“I think it’s very important that we say that we must remain within the United Kingdom customs union, it’s a principle that has always been there and a principle that will forever be there. We have to be entirely within the United Kingdom.”
“People have to get real and have to understand that we are part of the United Kingdom, will remain part of the United Kingdom and there has to be respect for that.
Ms Foster was asked about an EU-UK customs partnership for Northern Ireland, which is said to be the mooted compromise being worked on in negotiations.
It would mean the UK, including Northern Ireland, leaving the EU customs union but applying EU customs controls and rules, and collect EU tariffs on goods crossing the Irish Sea into Northern Ireland.
Where goods remain in the North or re-enter the rest of the UK, Northern Irish traders could claim back the difference, like a VAT rebate. If products are transported on from the North into the Republic or other parts of the EU, no rebate could be claimed.
When asked if she would accept “adhering to EU’s customs rules around tariffs”, Ms Foster replied:
“No, because we would have no say over those tariffs and would have no say in relation to how those tariffs were set. So I think it is very important to recognise why we voted against the backstop. If we go back to what was wrong with the backstop in Theresa May’s withdrawal agreement. There is no point reinventing that now and just putting that back in again. We have to see flexibility from the European Union just as we have shown flexibility around the single market regulations.”
Going in to the meeting Dutch foreign minister Stef Blok said companies in the Netherlands will have to be assured “there are no byways into the single market from Northern Ireland”.
The UK would have to give solid assurances on policing customs controls: “They have given some but not enough,” he said.
France’s Europe minister Amelie de Montchalin said of the prospects for an extension that France still insisted that one would only be granted if, like an election, “it could change the political dynamic”.
There is speculation in Luxembourg that, in the absence of a deal, leaders at the summit may agree to defer consideration of an extension until a second summit, at the end of the month, to allow Mr Johnson maintain his insistence that a deal remains possible that will allow the UK to leave on October 31st. – Additional reporting by Reuters