European Council president Donald Tusk said he was "absolutely sure" that Britain and the remaining 27 EU nations will find a solution to avoid a hard border in Ireland.
Speaking on the eve of the European Council summit, Mr Tusk said: "Trust me, our latest proposal when it comes to new guidelines, is also acceptable for Dublin and for London.
"I can say that our interpretation of the so-called 'December agreement' is almost identical compared to the British position.
"This is why I am absolutely sure that we will finally find a proper solution to avoid this risk of hard border between Ireland and Northern Ireland."