Brexit negotiations are stuck on three critical issues and "further effort" is needed to break the deadlock, UK and European Union leaders have said.
Prime Minister Boris Johnson and European Commission President Ursula von der Leyen issued a joint statement following an hour-long discussion on Saturday.
They said that while "progress has been achieved in many areas... significant differences remain on three critical issues: level playing field, governance and fisheries".
"Both sides underlined that no agreement is feasible if these issues are not resolved," the leaders added.
"Whilst recognising the seriousness of these differences, we agreed that a further effort should be undertaken by our negotiating teams to assess whether they can be resolved.
"We are therefore instructing our chief negotiators to reconvene tomorrow in Brussels.
"We will speak again on Monday evening."
The EU's chief Brexit negotiator Michel Barnier said: "We will see if there is a way forward. Work continues tomorrow."
Following the joint statement, Sky's Europe correspondent Adam Parsons said: "We've had months of ever-more intensive talks, and very little progress.
"A breakthrough will depend on compromise. And that will mean Michel Barnier being told he can go beyond his long-established mandate."
Ireland's Prime Minister Micheal Martin said he welcomed that negotiators will resume their discussions in Brussels tomorrow.
"An agreement is in everyone's best interests," he tweeted.
"Every effort should be made to reach a deal."
