Theresa May has told European Union leaders the UK is ready for Brexit talks to pick up, with the publication of a much-anticipated Brexit white paper to be published shortly.
But EU chief negotiatior Michel Barnier said today that while progress had been made – big differences remained.
He added that he hoped a British proposal would be "valuable and workable".
"On Brexit we have made progress, but huge and serious divergences remain, in particular on Ireland and Northern Ireland," Barnier told reporters. "Now we are waiting for the UK white paper and I hope it will contain workable and realistic proposals, but let me mention once again that the time is very short."
May met leaders of the bloc at a summit focusing on the migration crisis, with an agreement finally reached on that in the early hours of this morning.
A key focus of the UK Prime Minister though, was on Brexit, and she also issued a warning to the bloc's leaders about the risk to their citizens' safety should a Brexit deal on security not be reached.
As for concerns that Brexit talks are moving too slowly, May told reporters: "We are going to be publishing our white paper shortly and I want to see the negotiations accelerating and intensifying thereafter."
She had said she looked forward to talking to fellow European leaders about the "good progress" that had been made on the withdrawal agreement, and securing "our strong future partnership".
"I think both sides are keen to continue that work at a faster pace than we have done up until now, and certainly we would welcome that," May said.
The desire to ramp up negotiations, came amid question marks over the UK's place regarding key policing agreements after Brexit. May said that obstructing UK participation in law enforcement schemes after March 2019 on Britain's departure from the bloc, would mean EU leaders' ability to tackle terrorism would be impacted.
She warned that it would mean no longer being able to share real-time alerts for wanted persons, and a slower response to alerts for missing people on either side of the Channel.
May headed to Brussels for the EU summit amid building pressure over the lack of progress in negotiations.
Earlier this week, European business groups criticised Brexit negotiators from the UK and EUfor their failure to advance more on a deal for services.
The European Services Forum (ESF), which represents firms across Europe and the UK, wrote to chief negotiators Barnier and David Davis to urge them to “take all necessary actions to minimise business disruption”.
Meanwhile last week, pro-Brexit business leaders wrote to May urging progress in their respective hopes for a trade deal.
The letter, signed by Brexiters including former chancellor Nigel Lawson, MP John Redwood, and Wetherspoon chairman Tim Martin, say the UK should not be afraid to revert to a World Trade Deal under WTO rules if Brussels refuses a free trade deal.