ROME Pope Francis’s top diplomat says the rise of populism is a response to a “deep malaise” being felt by many Europeans, which is only aggravated by the migration crisis and economic problems on the continent.

Italian Cardinal Pietro Parolin, the Vatican’s Secretary of State, told Italy’s La Stampa the current flow of migrants and refugees into Europe is testing “the spirit of solidarity and subsidiarity” of the European Union, and acknowledged the large number of people fleeing to the continent poses a security problem.

“Terrorism certainly finds fertile ground in poverty, lack of jobs, and social marginalization,” he told the newspaper, but added that since World War II, Europe has tried to “free itself” from its cultural heritage and values, and this has created a vacuum in which young people cannot find the answers to their existential questions.

“They search for palliatives and substitutes,” Parolin said.

He said terrorism can be fought by bringing back Europe’s soul – it’s religious and cultural heritage – which has been hidden behind the “culture of consumerism.”

The cardinal also said newcomers must also respect the heritage of those who welcome them.

“While you can’t ignore those in need, there is also the need for immigrants to observe and respect the laws and traditions of the people who receive them,” Parolin said, adding that immigration “also poses a cultural challenge” to the spiritual and cultural heritage of Europe.

He said the authentic concerns of people are being taken up by populists, and these concerns should not be ignored by officials, because the recent history of Europe shows the “devastating effects” of populism.

Parolin’s remarks came during a discussion about this week’s celebrations marking the 60th anniversary of the Treaty of Rome, which established what is now the European Union.

Leaders from a score of European countries, as well as the EU institutions, will be gathering in the Italian capital for a summit to reflect on the future of the EU, and what it has accomplished over the past 60 years.

Parolin said the anniversary “reminds us that it is possible to work together,” and said the treaty signed on March 25, 1957, has given Europe “peace and development.”

He also said the EU shouldn’t forget its Christian foundations, and said Christianity is a “basic element” of the common heritage of Europe.

“These roots are the lifeblood of Europe,” Parolin said, drawing attention to how Christian principles were mentioned explicitly by those who signed the Treaty of Rome in 1957.

“Since then, a process slowly took over which increasingly relegated Christianity to the private sphere.”

The cardinal said Christians are called to “offer with conviction the testimony of their lives.”

Pope Francis is scheduled to meet with the European leaders in Rome for the anniversary at a special audience on Friday evening in the Vatican.