Pope Francis' visit with refugees and migrants in Greece this Saturday could be a moment of leadership at a time when political concerns overshadow the world's attention, said a relief agency leader in the country.

"The Pope's trip to the frontlines of the European refugee crisis comes at a critical time. The continent of Europe is currently experiencing a vacuum of leadership with the politics of the crisis oftentimes overshadowing the plight of those on the move," Josh Kyller of Catholic Relief Services told CNA.

Kyller is the U.S.-based relief agency's emergency coordinator for the refugee and migrant response in the region. He said the Pope is "making the ultimate statement by avoiding the politics."

"Instead, he draws our attention to the tens of thousands of those who are suffering."

Kyller spoke to CNA from Athens on April 13, shortly before Pope Francis' one-day visit to the Greek island of Lesbos, a major transit point for refugees and migrants seeking entry to Europe. He will be accompanied by the Orthodox Patriarch of Constantinople, Bartholomew, and Orthodox Archbishop of Athens and all Greece, Ieronymos II.

The Pope said April 13 he would go with them "to express my closeness and solidarity to the refugees and citizens of Lesbos and to all the Greek people (who are) so generous in their welcoming."

Most of the refugees arriving in Greece are from Syria, Afghanistan or Iraq. More than 80 percent of the new Syrian arrivals are Muslim.

Kyller said the Pope has shown that he welcomes everyone regardless of religious difference.

Upon arriving in Lesbos, Kyller said, Pope Francis will find a detention camp for migrants. But he will also find much more than that.

"He'll find a community of vacationers and retirees, and a lot of incredible volunteers. There are police and fences – and a lot of boats still coming and leaving. He'll encounter people with hopes, fears, anxiety, and confusion right next to people filled with good will, compassion and mercy."

"He'll see the best and the worst sides of people and politics. He will be welcomed, of course, and he will find a lot of despair that he will want to find a way to offer hope through grace."

Most of the refugees have traveled for weeks to arrive in Greece. They would rather have stayed in their homelands, but feared the violence there.

Since March 2011, over 250,000 people have been killed in the Syrian civil war. Millions more have been displaced.

"Refugees arriving in Europe have recounted in horrific detail the atrocities they witnessed within their homeland," Kyller said. "As one mother told a CRS staffer, 'You wouldn't put a child on this boat unless it's safer than your home'."

"Many risk their lives for this new start," he added. Many are targeted by traffickers and suffer exploitation and abuse. Some have spent all their savings or go into major debt to reach Europe.

Most of the refugees seek to reunite with their relatives in countries like Germany or Sweden.

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Kyller said that Catholic Relief Services' guiding principles includes solidarity. This is the idea that "loving (and helping) our neighbor has global dimensions."

"The Pope is the very embodiment of that principle," he said.

Before other European countries closed their borders to migrants, Greece had been struggling to keep up due to its fragile economy.

Over 150,000 refugees and migrants have arrived in Greece by sea so far in 2016. At the village of Idomeni, over 10,000 people who aim to move deeper into Europe are stranded near the Macedonian border.

"Following the closures, the situation has gotten even more severe," Kyller said. Conditions there "deteriorate by the day."

While the migrant crisis has caused security fears in parts of Europe, Kyller said that Greece is more focused on concerns related to the economy and the employment crisis.

Catholic Relief Services and its local partners like Caritas have helped over 300,000 people in Greece, the former Yugoslav Republic of Macedonia, Serbia, Croatia, Albania and Bulgaria.

"We continue to adapt our priorities to the evolving situation. The Caritas network is vast and well-integrated into each of the countries where we work. This fact helps us reach the least-served groups as well as the countries that support them," Kyller said.

Support for migrants and refugees includes food, winter clothing, sanitation, temporary shelter, legal aid and assistance in language translation.

There have been immigrant protests and clashes with police in Idomeni in recent days. On Sunday about 300 migrants, including women and children, were injured when they tried to break through the border fence on the Macedonian border. Police fired tear gas and bullets at them.

Police have arrested 14 pro-refugee activists from Britain, Germany and other European countries. They accused them of encouraging hundreds of migrants to storm the fence, the New York Times reports. The activists allegedly thought the action would generate sympathy and help re-open borders.