The future of Boris Johnson's Brexit deal hangs in the balance as EU officials say the outcome of talks should be known by the end of the day, BCC reports.
The EU's Donald Tusk said he would have "bet" on a deal 24 hours ago, but "doubts" had appeared on the UK side.
The PM is trying to get Tory Brexiteers and Democratic Unionists on board for his revised plan for Northern Ireland.
Likening talks to climbing Everest, Mr Johnson said the summit was "not far" but still surrounded by "cloud". He is in a race against time to get a deal before Thursday's crucial EU council meeting.
The BBC's political editor Laura Kuenssberg said she understood the issues between the UK, EU and Ireland were "pretty much sorted", but it was still not clear whether the DUP were ready to sign up or not.
