European Union President Donald Tusk Monday said Britain's closely-watched referendum on EU membership should be seen as a "warning signal" for the rest of the bloc, as he again urged Britons to stay in the European family.
"Whatever the UK vote is, we must take (a) long hard look on the future of the Union. Would be foolish to ignore such a warning signal," Tusk wrote on Twitter, three days before Britons go to the polls in a vote that has polarised the nation and triggered heated debate across the EU.
"I appeal to the British citizens: Stay with us. We need you. Together we will cope with future challenges. Apart it will be more difficult," he added.
Speaking in Lisbon after a meeting with Portuguese Prime Minister Antonio Costa, Tusk also warned of the "unpredictable" political and geopolitical consequences of a possible Brexit.
"I have no doubt that our enemies, internal and external enemies, will open a bottle of champagne if the result of referendum is negative for us," he said at a press conference.