Theresa May met Jean-Claude Juncker for a working dinner
The UK and EU have agreed "efforts should accelerate" over Brexit negotiations following the British Prime Minister's visit to Brussels.
Following a working dinner in the Belgian capital on Monday night, Theresa May and European Commission president Jean-Claude Juncker described a "constructive and friendly" exchange as they prepared for a crunch EU summit this week.
In a joint statement, they said: "The Prime Minister and the President of the European Commission reviewed the progress made in the Article 50 negotiations so far and agreed that these efforts should accelerate over the months to come."
Mrs May made the previously unannounced trip to meet the top EU official as Brexit talks remain deadlocked over key divorce issues - including the UK's financial settlement.
Both Brexit Secretary David Davis and the EU's lead negotiator Michel Barnier were also due to join the dinner, along with Mrs May's Brexit adviser OIly Robbins and Mr Juncker's chief of staff Martin Selmayr.
Her visit comes before a European Council summit this week, where leaders of the 27 other EU member states will be updated on the progress of the UK's exit negotiations.
The EU27 will also decide whether to agree the start of the EU's internal preparations for the second phase of Brexit talks, on transitional arrangements and future trading terms.
If they do, it could offer the UK government some hope of negotiations progressing to discussions on the future UK-EU relationship before the end of the year, despite suggestions Germany is hardening its stance on negotiations.
Ahead of her meeting with Mr Juncker, Mrs May held calls with Taoisech Leo Varadkar, German Chancellor Angela Merkel and French President Emmanuel Macron in a concerted diplomatic push.
The joint statement from Mr Juncker and Mrs May revealed the pair also discussed "current European and global challenges" in a "broad" discussion, including efforts to combat terrorism and Donald Trump's decision not to recertify the Iran nuclear deal.
Earlier, Mr Juncker refused to disclose what issues he would discuss with Mrs May in Brussels but added a "post mortem" would emerge after their talks.
Despite what Mr Barnier has termed a "disturbing" impasse in negotiations over Britain's exit payment to the EU, Mrs May was not expected to make any fresh offers on withdrawal issues.
Mr Juncker has insisted the UK will "have to pay" to activate trade talks.
Ahead of Mrs May's trip to Brussels, British Foreign Secretary Boris Johnson urged the EU to "get on" with Brexit negotiations.
"It's ready for the great ship to go down the slipway and on to the open sea and for us to start some serious conversations about the future and the new relationship," he said.
The last time Mr Juncker had dinner with Mrs May, in Downing Street in April, he was reported to have told Mrs Merkel Mrs May was "on a different galaxy" over Brexit.