Pope Francis on Saturday condemned the political use of fear and the building of walls, describing the refugee crisis as “a problem of the world” and urging political leaders to do more, according to America magazine.

The pope did not name names and did not refer to the upcoming U.S. presidential election, but he spoke about issues that have come up in the 2016 campaigns, including immigration and refugees. The speech, given in Spanish, included a quote from the Rev. Martin Luther King Jr.

“No tyranny can be sustained without exploiting our fears,” the pope said, according to comments published by the Vatican Radio. “Citizens are walled-up, terrified, on one side; on the other side, even more terrified, are the excluded and banished.”

Fear “is fed and manipulated,” Pope Francis said. “Because fear – as well as being a good deal for the merchants of arms and death – weakens and destabilizes us, destroys our psychological and spiritual defenses, numbs us to the suffering of others, and in the end it makes us cruel.”

Pope Francis gave his remarks Saturday evening during a meeting at the Vatican with participants in the World Meeting of Popular Movements, a collection of grass-roots organizations that include the poor and the unemployed. The pope urged the defeat of “false prophets who exploit fear and desperation, who sell magic formulas of hatred and cruelty or selfish well-being and illusory security,” according to comments published by Catholic News Service.

Francis said that mercy is the “best antidote” to fear, according to CNS. It works better than antidepressants, he said, and is “much more effective than walls, iron bars, alarms and weapons. And it is free.”

Trump has proposed building a wall along the U.S.-Mexico border to keep undocumented immigrants from entering the United States. After he visited the border during a visit to Mexico in February, the pope said that politicians who propose building walls instead of bridges are “not Christian,” leading to a scuffle with Trump. Vatican officials said later that the pope was not speaking about specific candidates.

Trump has also proposed a ban on Muslims and refugees from countries experiencing terrorism. A newly named cardinal, Archbishop of Indianapolis Joseph Tobin, made headlines last year when he openly defied Republican Indiana Gov. Mike Pence’s decision to try to block Syrian refugees from the state. Pence, who is Trump’s vice presidential running mate, joined dozens of governors last year in objecting to the federal government’s program to resettle refugees from Syria in the Unites States, citing security risks. The bishops, including Tobin, openly challenged the governors.

“No one should be forced to flee his or her homeland,” Francis said on Saturday, according to CNS. “But the evil is doubled when, facing terrible circumstances, the migrant is thrown into the clutches of human traffickers to cross the border. And it is tripled if, arriving in the land where he or she hoped to find a better future, one is despised, exploited or even enslaved.”

The Obama administration announced in September that the United States is planning to accept 110,000 refugees in 2017. A vice president at Catholic Relief Services said that aid organization welcomed the news, but that it was not sufficient enough to address “the 65 million globally displaced people around the world right now.”

On Saturday, Francis quoted from one of the sermons of King, the late civil rights activist. “Hate for hate only intensifies the existence of hate and evil in the universe,” he said.

Francis said politics is not the place for “anyone who is too attached to material things or to the mirror, those who love money, lavish banquets, sumptuous houses, refined clothes, luxury cars.” Seeking power or money “sullies the noble cause” of politics as service, the pope said.

“Fight the fear with a life of service, solidarity and humility on behalf of the people, especially those who suffer,” he said, according to CNS. “Against the terror, the best remedy is love. Love heals all.”

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