German Chancellor Angela Merkel urged the European Union's remaining 27 members on Tuesday to stick together during talks on Britain's exit from the bloc, which began on Monday.
Merkel also said the talks were important for the future of European integration.
Brexit was a setback but election results in the Netherlands and France this year have presented an opportunity for the EU to push ahead, she added.
"Let's stay together, let's not divide from each other," she said with reference to the remaining EU 27 and the 19 euro zone countries.
"This is not just about the exit of Britain, with which we want to remain friends, with which we want to live in a good partnership, but it is also about the future of the European Union," she said at a German industry conference.
"The four freedoms that give us the internal market must not be jeopardised," she said with reference to the EU's freedoms of movement of goods, capital, people, and services. "This will be significant at the exit negotiations."
Merkel said she wanted the talks to be conducted "in a good spirit" and that Britain's position would become evident in the coming months.
"We will of course implement what Britain pitches, but in a way that the interests of the 27 member states are safeguarded."