EU summit chair Donald Tusk said on Friday that the bloc would start "exploratory contacts" with Britain on what London wants in a future trade relationship, as well as starting discussion on a post-Brexit transition.
He was speaking to reporters after an EU summit that gave a formal green light to opening a new phase of negotiations. Full talks on future trade will not start until after another summit in March to agree the EU's own negotiating objectives.
EU chief executive Jean-Claude Juncker praised British Prime Minister Theresa May for a deal on divorce terms last week. He called her a "tough, smart, polite and friendly negotiator" and joked that he had obliged her to travel to Brussels for a 7 a.m. meeting a week ago.