The president of the European Commission, Jean-Claude Juncker, sought on Wednesday to rally support for the European Union, saying the bloc battered by the UK Brexit referendum was not about to break up despite its existential crisis.

In setting out the Commission's plans for the first time since the UK voted to exit the EU on June 23, Juncker highlighted the British referendum as a warning that the EU faces a battle for survival against nationalism in Europe.

"The European Union doesn't have enough union", Juncker told the European Parliament in Strasbourg. "There are splits out there and often fragmentation exists ... That is leaving scope for galloping populism," he said.