Juncker added that he hoped the European Council later this month would make "enough progress" that "we can see it through in November".
Some Brexiters overlook that the EU's version of a so-called Canada deal incorporates a guarantee to prevent a hard border on the island of Ireland, which would keep Northern Ireland in the EU customs union and single market.
"What I do know is that we need a backstop, a protocol on Ireland and N Ireland as part of a withdrawal agreement, that's essential", he said. But there are still wrinkles to iron out, an European Union official said after Friday's meeting, and it will hinge on May's ability to keep her Northern Irish allies onside.
"The EU is serious about getting the best possible deal", he said. "He wants to tear up our guarantee to the people of Northern Ireland", she said.
"That's how it was in Salzburg, and that's also how we will work in the coming days".
A member of EU Brexit negotiator Michel Barnier's team briefed diplomats of the 27 states remaining in the bloc on latest developments on Thursday afternoon.
Magnitude 5.9 natural disaster shakes northern Haiti
President Jovenel Moïse also tweeted that civil protection workers are already working to assist people in affected areas. Geological Survey, the quake's epicenter was about 19 kilometers northwest of the coastal town of Port-de-Paix.
Mrs May has been invited to address the other 27 European Union leaders over dinner on 17 October, to give her a chance to convince her peers that a solution can be found to the sticking points in Britain's tortuous negotiations to leave the bloc.
Critics were quick to point out that Brussels' uncompromising stance on the Irish border appears to contradict this statement, as a trade deal allowing some diversion on goods regulations, unlike Theresa May's Chequers proposals, would require checks on the border. "Now you discover new problems nearly daily, on both sides".
But Mrs May has said a deal like Canada's would not prevent a visible, physical border being needed in Northern Ireland - a key commitment of both sides - because of the extra checks that would be needed on goods.
The Irish border impasse has heightened fears that the United Kingdom could find itself crashing out of the bloc without a deal.
"Continued concerns over the Italian budget deficit and sovereign rating contrasts with what seems to be an improving Brexit outlook", Morgan Stanley analysts said in a note, pointing to possible further downside momentum towards 87 pence per euro.
Britain could not only have a free trade accord like that with Canada but also extremely close relations in security, foreign policy and other areas, Tusk said after meeting Irish Prime Minister Leo Varadkar. The UK government has acknowledged that could leave planes grounded and trucks backed up at British ports.