National borders are "the worst invention ever", European Commission president Jean-Claude Juncker has claimed.
The comments by Brussels' top official were dismissed by Theresa May, whose spokeswoman said "it is not something that the Prime Minister would agree with".
Mr Juncker's remark comes as nations across Europe have looked to tighten their borders in response to the growing migrant crisis which has threatened to overwhelm some countries.
He made the comments to the European Forum Alpbach, according to its website.
The website said he told the audience: "Borders are the worst invention ever made by politicians", and said solidarity must be given to refugees and their children.
Responding to the comments, Mrs May's official spokeswoman said: "It is not something that the Prime Minister would agree with and, indeed, you have heard the Prime Minister talk about the views that the British people expressed in the referendum.
"The British people think that borders are important, having more control over our borders is important, and that is an issue we need to address."
Mr Juncker also said Brexit was not a pretty moment, and one which the EU must overcome, according to the website's report.
He said: "In the concentration of globalisation and European problems, we must not lose our way."
It comes as the leaders of Germany, France and Italy - Europe's three biggest countries - meet on Monday to discuss the way forward for the EU in the wake of Britain's historic decision to leave.
German chancellor Angela Merkel, the French president Francois Hollande and Italy's prime minister Matteo Renzi are meeting on the Italian island of Ventotene for talks.
