Leaders from across Europe have gathered in Rome to mark the 60th anniversary of the signing of a treaty which led to the formation of the EU.

Taking place just days before British Prime Minister Theresa May launches the Brexit process on Wednesday the summit was a chance for the heads of 27 member nations - not including the UK - to discuss the future of the bloc after Britain's departure.

Addressing attendees European Commission President Jean-Claude Juncker described Brexit as "a tragedy" while EU Council President Donald Tusk called for sustained unity among nations saying it was the only way for the EU to survive.

Tusk said: "Only a united Europe can be a sovereign Europe in relation to the rest of the world.

"Only a sovereign Europe guarantees independence for its nations, guarantees freedom for its citizens. "

The anniversary event was also used as an opportunity to reaffirm European unity with all 27 leaders that attended signing a new Rome Declaration which enshrined the principles of the bloc and said that "European unity is a bold, farsighted endeavour."