British Brexit minister Dominic Raab is holding talks with the European Union's chief Brexit negotiator Michel Barnier in Brussels, on the same day as the EU's 27 ambassadors were called to a meeting.
"With several big issues still to resolve, including the Northern Ireland backstop, it was jointly agreed that face-to-face talks were necessary ahead of this week's October European Council," a spokesman for Raab said.
Ambassadors for the 27 member states of the European Union were summoned to a meeting on Brexit in Brussels at 4.30pm (GMT), according to diplomatic sources. The meeting will involve representatives for the EU's member states excluding Britain.
British Prime Minister Theresa May heads to Brussels on Wednesday for a summit when both sides want to sign off on a draft withdrawal agreement to set out the terms for Britain's divorce from the EU.
It comes as DUP leader Arlene Foster has said that a no-deal Brexit was now the "likeliest outcome", according to leaked emails seen by the Observer newspaper.
According to the private email exchange between senior UK officials seen by the newspaper, Ms Foster gave her views during a dinner with the leader of Conservative MEPs, Ashley Fox.
Ms Foster indicated the DUP was "ready" for a no-deal scenario, which she now believed was on the cards.
The DUP leader also expressed disappointment over her meeting with EU chief negotiator Michel Barnier, and described him as "difficult and hostile".
Yesterday, Ms Foster said she appreciated the risks of a no-deal Brexit but said "the dangers of a bad deal are worse".
She described current plans as amounting to "the annexation of Northern Ireland" by the EU.
"The DUP's actions this week are not as some have suggested about 'flexing muscle'," she said, adding: "This is no game."
"Anyone engaging in this in a light-hearted way foolishly fails to grasp the gravity of the decisions we will make in the coming weeks," she said.
Writing in the Belfast Telegraph, Ms Foster said the backstop arrangement would not be a temporary measure.
"It would be the permanent annexation of Northern Ireland away from the rest of the United Kingdom and forever leave us subject to rules made in a place where we have no say," she said.
Ms Foster will meet with Taoiseach Leo Varadkar in Dublin on Monday to discuss a number of current issues.
In the absence of a comprehensive EU-UK trade partnership after Brexit, the EU is seeking a backstop arrangement whereby Northern Ireland would effectively remain subject to the bloc's regulations to avoid a hard border.
But the DUP, whose support Mrs May needs to pass legislation in Parliament, vehemently opposes any proposals under which the province would be treated differently to the rest of the UK.
Britain wants any backstop arrangement to be time-limited.
Hardline supporters of Brexit in Mrs May's ruling Conservative Party fear it could be used to keep the whole UK inside a customs union indefinitely with the EU.
