Germany and Ireland's foreign ministers on Friday said they believe a Brexit deal is still possible, even though British Prime Minister Boris Johnson has warned that a no-deal scenario was very likely.

"We believe that an agreement is difficult but still possible," German Foreign Minister Heiko Maas said ahead of a meeting with his Irish counterpart Simon Coveney in Berlin. "We will keep negotiating ... as long as a crack of the window is open."

Coveney added that he believed "it's possible to get a deal on a future relationship and on a trade agreement."