National borders are the "worst invention ever," the head of the European Union (EU)'s executive arm said on Monday, at a time when many countries in the bloc are looking to strengthen borders following terrorist attacks and a surge in refugee and immigrant numbers. In a speech at the European Forum Alpach in Vienna, EU Commission President Jean-Claude Juncker said solidarity must be shown to refugees and their children. "Borders are the worst invention ever made by politicians," he added.



Jean-Claude Juncker speaks during a media conference at EU headquarters in Brussels. Dursun Aydemir | Anadolu Agency | Getty Images

His comments were quickly shot down by new U.K. Prime Minister Theresa May. "This is not something the Prime Minister would agree with … 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," a spokesperson for May said, according to media reports. Germany has reinforced controls at its border with Switzerland, Swiss finance minister Ueli Maurer said on Sunday, according to media reports. This follows a surge in the number of migrants crossing through Switzerland and a tightening in controls at the Swiss-Italy border. The number of Syrian refugees in Europe continues to rise, but remains low compared to numbers in neighboring countries like Turkey. Over 1 million Syrians made asylum applications in Europe in the five years to June 2016, according to data from the United Nations. Following several Islamist terror attacks in France, French President Francois Hollande has stressed the need for EU nations to tighten borders and share intelligence. "To have security we need frontiers that are controlled, so that is why we are working to reinforce coastguards and border guards," he said on Monday, according to media reports, following a meeting with his German and Italian counterparts in Italy.