We have to work on drafting an operational backstop, and for that I've asked Dominic and his team to give us a certain amount of data which is necessary for the technical work which we need now on the nature, the place, where and how the necesseary controls and checks take place.
One of the biggest sticking points is the future regulation of the border between the Republic of Ireland, an European Union member, and Northern Ireland, which will leave the European Union as part of the United Kingdom.
Earlier, Mr Barnier said a backstop is "essential to conclude the negotiations", stating: "With no backstop there will be no agreement".
Michel Barnier is refusing to back down on erecting a border in the Irish Sea to avoid a hard border on the island of Ireland, and has publicly asked the British government for data to prove that the checks on goods flowing within the territory of the United Kingdom would be few in number.
The backstop is a safety net agreed in December that guarantees an invisible border, though there is no agreement to this date on how it will work.
But London has so far rejected the idea of the backstop, saying it would create a border between Northern Ireland and the rest of the UK.
At a press conference in Brussels, Mr Raab said "valuable progress" had been made in the negotiations, and that both sides were edging towards an agreement.More news: European Union Set to Scrap Daylight Saving Time
"It's a matter of some urgency".
The UK Government insists that any backstop position should include the UK as a whole.
Mr Raab said that any solution must be workable for communities in Northern Ireland and the Republic of Ireland.
Barnier said unresolved issues included geographical indications, the role of the EU's top court in policing the agreement and data protection, among others.
"The solutions must be workable".
In response to Barnier's latest comments, GBPUSD was barely changed after its Wednesday gains, suggesting the uptrend in the pair that began two weeks ago will likely extend higher.
Raab, whose predecessor David Davis resigned in July over differences with Prime Minister Theresa May's negotiating strategy, said he was "stubbornly optimistic" that a deal could be reached.