Ireland's Prime Minister Leo Varadkar is welcomed by European Union's chief Brexit negotiator Michel Barnier ahead of a meeting in Brussels, Belgium October 4, 2018. REUTERS/Yves Herman

BRUSSELS (Reuters) - A divorce deal with Britain requires a legally sound solution for the border between Ireland and Northern Ireland, the European Union’s Brexit negotiator Michel Barnier said on Thursday after talks with Irish Prime Minister Leo Varadkar.

“We are in the final stage of the #Brexit negotiations & working hand-in-hand w/ the Irish gov. To agree to any deal, we need to have a legally sound backstop solution for Ireland and Northern Ireland,” Barnier said in a tweet.