Pope Francis at the traditional Good Friday cross procession denounced those committing "terrorist acts" while profaning God's name and lamented what he called "anesthetized" consciences over war refugees flooding Europe.

Francis renewed his condemnation of what he has called indifference and inhospitality to those risking their lives in unseaworthy smugglers' boats in hopes of finding refuge on European shores from war and other violence.

Evoking the image of Jesus on the cross, Francis said: "we see you in the faces of children, of women and people, worn out and fearful, who flee war and violence and who often only find death" and people who refuse to deal with them.

Francis called the Mediterranean and Aegean Seas, two major routes for refugees and migrants, "insatiable cemeteries, reflections of our indifferent and anesthetized conscience."

In reference to deadly extremist attacks in Europe, Iraq and elsewhere, Francis denounced "expressions of fundamentalism" and "terrorist acts committed by followers of some religions which profane the name of God and which use the holy name to justify their unprecedented violence."

Earlier in the week, Francis called the deadly attacks at a Brussels metro station and airport "cruel abominations."

Wearing a long white coat against the evening's chill, Francis had presided over a torch-lit procession at the ancient Roman arena, a symbol of early Christian martyrdom.

Again, suggesting the image of Jesus' dying on the cross, Francis said: "We see you raised up in our sisters and brothers killed, burned alive, throats slit and decapitated by barbarous blades amid cowardly silence." Throughout his papacy, Francis has repeatedly lamented the persecution and killing of Christians for their faith by extremists in the Middle East.

In his prayer ending the Colosseum service, he said the "certainty" of God's love won't be obscured by "the apparent victory of evil."

The Good Friday service drew thousands of pilgrims and Romans who patiently submitted to security checks, part of stepped-up measures across much of Europe after the Brussels attacks.

Hours before the pope arrived, police led explosives-detecting dogs through inspections inside and outside the Colosseum. Later, police waved metal-detecting wands across the faithful and searched their bags and knapsacks.

Another security challenge comes on Sunday, when tens of thousands of people are expected in St. Peter's Square for Easter Mass celebrated by the pope.