The symposium was convened at the Vatican to highlight the role of faith-based organizations in advancing religious freedom, combatting human trafficking, and providing humanitarian aid.
"The stakes today are arguably higher than they were even during the Cold War," Pompeo said.
"More than 80% of mankind lives in places where religious freedom is threatened or entirely denied. Approximately 71 million people around the world are displaced as refugees, roughly 25 million people are caught in human trafficking situations, and it is not coincidence that this has happened as unfree societies have proliferated," he said.
The US Department of State this year launched the International Religious Freedom Alliance, a multilateral organization to advance religious freedom issues worldwide. "We humbly ask the Holy See to join us," Pompeo said. "What could be more powerful than our voices all together calling for the freedom to worship God?"
Archbishop Paul Gallagher, Vatican Secretary for Relations with States spoke at the symposium opening about the need to "promote peaceful coexistence and peaceful societies." He highlighted Pope Francis' joint declaration on human fraternity signed in Abu Dhabi, and said that the Holy See seeks to develop an international network of religious leaders to promote "healthy pluralism."
Pompeo commended Pope emeritus Benedict XVI and Pope Francis for speaking out in defense of Asia Bibi, the Pakistani Catholic woman whose life was threatened under a blasphemy law.
As U.S. Embassy to the Holy See marks its 35th anniversary this year, Pompeo spoke fondly of St. John Paul II and US President Ronald Reagan's partnership during the Cold War.
"Think of the millions of believers who can live with dignity and purpose, who can now worship without fear, thanks to the joint efforts of a pope and a president," Pompeo said.
Courtney Mares is a Rome Correspondent for Catholic News Agency. A graduate of Harvard University, she has reported from news bureaus on three continents and was awarded the Gardner Fellowship for her work with North Korean refugees.