"Huge and serious differences remain between the UK and EU in Brexit talks, the EU's chief negotiator has warned."
Michel Barnier invited UK negotiators back to Brussels next Monday, warning: "The time is very short."
Talks over the terms of the UK's withdrawal from the EU in March next year.
The UK says it will be blocked by EU negotiators.
Arriving on the second day of the European Council meeting on Friday, Mr Barnier said: "We have made progress in the future, and in particular Ireland and Northern Ireland."
He also said he hoped to see "workable and realistic" UK and EU should look like
"The time is very short We want to deal with a deal, the time is short and I'm ready to invite you to the UK delegation to come back to Brussels next Monday."
The prime minister has called for a meeting at the moment with the European Union.
Her own cabinet is over what the UK's customs arrangements after December 2020 should look like, when the transition period agreed with the EU is due to end.
On Thursday, Mrs May said that it was a future partnership with the EU.
"I think both sides are not continuing to work at a faster pace than we have welcome that, "she said.
But the United Kingdom wants to see the European Union in the future."
But she urged fellow EU leaders to share their negotiators in the UK like the Prel mechanism for sharing DNA profiles, the Second Generation Schengen Information System ̵
Mr Barnier has argued the UK can not remain part of some policing agree Brexit Mentioned the European Court of Justice and Free Movement Rules.
He said the EU wanted "ambitious partnership, on trade as well as security", but it had to be based on our values and our principles, thus respecting the UK red lines ".