CIUDAD JUAREZ, Mexico — In a moment filled with powerful political symbolism, Pope Francis prayed Wednesday at Mexico’s dusty northern border for the thousands of migrants who have died trying to reach the United States and appealed for governments to open their hearts, if not their borders, to the “human tragedy that is forced migration.”

“No more death! No more exploitation!” he implored.

It was the most poignant moment of Francis’ five-day trip to Mexico and one of the most powerful images in recent times: History’s first Latin American pope, who has demanded countries welcome people fleeing persecution, war and poverty, praying at the border between Mexico and El Paso, Texas, at a time of soaring anti-immigrant rhetoric in the U.S. presidential campaign.

Francis stopped short of calling for the U.S. to open its borders during a Mass just 800 yards from the frontier. But in his homily beamed live into the Sun Bowl stadium on the El Paso side, Francis called for “open hearts” and recognition that the thousands of Central and South Americans who are fleeing gangland executions and extortion in their homelands are victims of the worst forms of exploitation.

MERCY FOR MIGRANTS

“We cannot deny the humanitarian crisis which in recent years has meant the migration of thousands of people, whether by train or highway or on foot, crossing hundreds of kilometers through mountains, deserts and inhospitable zones,” he said. “They are our brothers and sisters, who are being expelled by poverty and violence, drug trafficking and organized crime.”

And then, in a pointed message, Francis added a politically charged greeting to the 30,000 people gathered in the Sun Bowl to watch the simulcast on giant TV screens.

“Thanks to the help of technology, we can pray, sing and celebrate together this merciful love which the Lord gives us, and which no frontier can prevent us from sharing,” Francis said in Spanish. “Thank you, brothers and sisters of El Paso, for making us feel like one family and the same Christian community.”

Francis, a son of Italian immigrants to Argentina, had wanted to cross the border in solidarity with other migrants when he visited the U.S. last fall.

TRUMP’S DISSENT

That wasn’t possible for logistical reasons, so he did the next best thing on Wednesday by coming within a stone’s throw of the fence and laying a bouquet next to a large crucifix that is to remain at the site as a monument to his visit. As the faithful looked on from both sides of the border, Francis blessed the cross and three smaller ones, which the Vatican said were to be sent to the diocese of Ciudad Juarez, Las Cruces and El Paso.

While migrant activists on both sides of the border cheered the gestures, Republican presidential hopeful Donald Trump criticized it last week as a politicized and ill-informed move.

“I don’t think he understands the danger of the open border that we have with Mexico,” Trump said in an interview with Fox television. “I think Mexico got him to do it because they want to keep the border just the way it is. They’re making a fortune, and we’re losing.”

He and Sen. Ted Cruz have vowed to expel the estimated 11 million immigrants in the U.S. illegally and build a wall along the border from Texas to California.

The border Mass marked the climactic end of Francis’ five-day swing through some of Mexico’s poorest and most marginal states, where drug-fueled violence has soared thanks to the complicity of police and other public institutions. Francis took both church and state to task for failing their people and urged the next generations to resist the lure of the drug trade.

Wednesday, Francis warned that without jobs, Mexico’s youth risk being seduced into the drug trade.

“God will hold today’s slave-drivers accountable,” he warned.