The UK Government has warned it will not be bound by an "artificial deadline" as the European Commission revealed it has received "documents" on its Brexit proposals.
The announcement comes after Finnish Prime Minister Antti Rinne claimed a new deal must be presented by the UK in the next 12 days.
The UK seemingly dismissed this timetable, insisting formal written solutions will be submitted "when we are ready" instead.
The "series of confidential technical non-papers" received by the Commission reflect the Government's Brexit ideas, its statement claims.
A Government spokeswoman said there have been "detailed discussions" with the commission's Taskforce 50 - the unit dealing with Brexit - in recent weeks.
"We have now shared in written form a series of confidential technical non-papers which reflect the ideas the UK has been putting forward," she said.
"We will table formal written solutions when we are ready, not according to an artificial deadline, and when the EU is clear that it will engage constructively on them as a replacement for the backstop."
A European Commission spokeswoman said there will be technical discussions on Thursday and Friday on some aspects of customs, manufactured goods and other areas.
"Then the discussion will also take place at political level because Michel Barnier, the commission's chief negotiator, will meet Steve Barclay [Brexit Minister] on Friday," she added.
European Commission president Jean-Claude Juncker has told Boris Johnson that a Brexit deal is both "desirable and still possible".
Mr Juncker spoke to the Prime Minister by phone on Wednesday and said their meeting on Monday was "friendly, constructive and, in part, positive".
A European Commission spokeswoman told a press conference in Brussels: "President Juncker reiterated what he said in the European Parliament yesterday, namely that a deal is desirable and still possible.
"He repeated that he thought Monday's meeting was friendly, constructive and in part positive."
Following his "working lunch" with Mr Johnson in Luxembourg on Monday, Mr Juncker later spoke to German chancellor Angela Merkel about the meeting.