Pope Francis said Europe faced a "vacuum of values" during an audience with EU leaders in the Vatican on Friday. Ahead of a celebration for the anniversary of the Treaty of Rome on Saturday, Francis condemned anti-immigrant populism and extremism as mortal threats to the bloc.

"When a body loses its sense of direction and is no longer able to look ahead, it experiences a regression and, in the long run, risks dying," he told heads of state and government from 27 EU member states, as well as EU Commission President Jean-Claude Juncker.

"The first element of European vitality must be solidarity," he said, arguing that this would be "the most effective antidote to modern forms of populism."

The Argentinian-born pontiff told the leaders they needed to promote Europe's "patrimony of ideals and spiritual values" more vigorously. Francis said the EU needed to close the gap between its citizens and institutions, adding that Brussels was "often perceived as distant and inattentive."

Among the attendees at the audience in the Vatican were German Chancellor Angela Merkel and Romania's President Klaus Iohannis

In a message likely aimed at US President Donald Trump as well as EU leaders, Francis urged Europe not to close in on itself and resurrect walls in the struggle to cope with mass immigration from conflict zones.

He said that a hostile mindset towards refugees showed many Europeans were experiencing a worrying "lapse of memory." He said many people had forgotten that Europe experienced mass migration during and in the aftermath of World War II.

"What efforts were made to tear down [the Iron Curtain]," he said. "Yet today the memory of those efforts has been lost. […] Forgotten […] is the tragedy of separated families, poverty and destitution born of that division."

On Saturday, EU leaders will celebrate the founding of the European Union. On March 25, 1957, six nations signed Treaty of Rome, establishing the European Economic Community, the EU's predecessor organization. Today, the EU is the world's largest trading bloc and encompasses 28 nations.

Leaders from 27 EU states attended the ceremony in the Vatican ahead of the Treaty of Rome's anniversary celebration

While the EU was long seen as being on an upswing - with rising life expectancy, solid prosperity and few military conflicts - the bloc has recently suffered a few major setbacks. Economic turmoil and disagreements over how to handle an influx of migrants have put the future of the union in question. Next week, Britain is expected to officially trigger its exit negotiations following last year's pro-Brexit vote. British Prime Minister Theresa May will be notably absent from the anniversary celebrations in Rome.

mb/sms (AFP, AP, Reuters)