Estonia, EU – Baltic States, Legislation

"What is important is for the UK's withdrawal process not to cause needless uncertainty," Paet said, adding that 27 member states have to draw their own conclusions from the Brits' exit and focus on a thorough reform of the EU. "The outcome of the referendum showed that the EU has become distant to many citizens and the benefits of membership have been forgotten."

Speaking about the future of the UK, Paet said it's not known yet where and how the country will be positioned in relation to the EU in the future. "London will now have to deal also with keeping the nation together. What steps Scotland and Northern Ireland are going to take will be seen in the near future," he said.

EU27 must keep a very cool head to avert a possible domino effect from the referendum, Paet underscored.

In his words, the outcome of the referendum opened the door to a new crisis in the EU and added a huge bundle of problems of an as yet indeterminate scope to the previous four crises – the refugee crisis, tense relations with Russia, terrorism and economic troubles. The outcome of the referendum is the biggest setback to European cooperation since World War II, he said.

The European Parliament gathered on Tuesday in Brussels for an extraordinary meeting to debate the outcome of the British referendum and its consequences for the future of the EU. MEPs adopted a resolution on the subject.