British Prime Minister Theresa May said Monday that she was still "confident" of a positive outcome to Brexit talks this week, despite Britain and the EU failing to strike an accord in crunch talks in Brussels.

"On a couple of issues some differences do remain that require further negotiation and consultation and those will continue, but we will reconvene before the end of the week, and I am also confident we will conclude this positively," May told reporters after a meeting with European Commission chief Jean-Claude Juncker.