U.S. leaders called for a worldwide “grassroots” movement to fight religious persecution at a global religious freedom gathering on Tuesday.

The “iron curtain” of religious persecution must “come down now,” U.S. Ambassador-at-Large for International Religious Freedom Sam Brownback stated on Tuesday at the opening of the State Department’s Second Annual Ministerial to Advance Religious Freedom. “Let this be the beginning of a global grassroots movement for religious freedom,” he said.

The Ministerial, held in Washington, D.C. from July 15-19, features over 1,000 religious and civil society leaders from around the world, along with over 100 foreign delegations and leaders of non-governmental organizations.

Over 20 survivors of religious persecution are also in attendance at the Ministerial, which will feature discussions of global religious persecution and on forming policies and partnerships to advance and promote religious freedom around the world.

Eighty percent of the world’s population lives in an area with religious restrictions, the State Department estimates. Secretary of State Mike Pompeo on Tuesday emphasized that freedom of religion is a fundamental, and public, right.

“All people must be permitted to practice their faith openly” whether at home, in public, or at a house of worship, Pompeo stated in his remarks opening the Ministerial.