In a historic move, Secretary of State John Kerry announced that Christians, Yezidis, Shi’a Muslims and other religious and ethnic minorities were found victims of ISIS genocide by the U.S. State Department.

“My purpose here today is to assert in my judgment, Daesh is responsible for genocide against groups in areas under its control, including Yazidis, Christians and Shiite Muslims,” Kerry said at the announcement March 17, referring to ISIS by an acronym of its Arabic name.

Kerry also accused ISIS of “crimes against humanity” and “ethnic cleansing.”

The move came amidst pressure from lawmakers and advocacy groups after a State Department spokesperson announced an anticipated delay of the congressionally mandated March 17 deadline for a decision on the matter.

It marked the first time the U.S. has declared a genocide is taking place since Darfur in 2004, and bears international significance before the United Nations, which considers genocide the “crime of crimes” because it involves the intentional destruction, “in whole or in part,” of an entire people. It is also only the third time that the U.S. House of Representatives has applied the term to an ongoing conflict.

The European Union had already unanimously declared a genocide of religious minorities in the Middle East in February. The U.S. declaration could add further pressure on the United Nations Security Council to declare genocide and refer the matter to the International Criminal Court, where the perpetrators could be tried.

Thursday’s announcement comes after many advocates for Christians in the Middle East petitioned for the declaration. Among them was Archbishop Jose H. Gomez of Los Angeles, who said in a recent column that the U.S. bishops and Pope Francis already considered the violence against Christians in the Middle East a form of genocide.

“Violence and torture are the daily cost of discipleship for Christians all over the world today — but especially in the Middle East. And the world community — government leaders, international authorities, the media and, sadly, even local churches — do not seem all that concerned,” he wrote.

“It is clear that what the so-called Islamic State is doing to Christians and other minority groups in Iraq and Syria fits the United Nations’ definition — violence and killing with ‘intent to destroy, in whole or in part, a national, ethnical, racial or religious group,’” he continued.

Archbishop Gomez also signed the “Stop the Christian Genocide” petition, cosponsored by the Knights of Columbus and advocacy group In Defense of Christians. He joined several noteworthy politicians in the signing of the petition, including former Secretary of State and Democratic presidential front-runner Hillary Clinton, GOP presidential candidate Senator Ted Cruz and Senator Marco Rubio.

The petition included the signatures of several other high-profile Catholic cardinals and bishops as well, including Cardinal Timothy M. Dolan of New York, and Archbishops Charles J. Chaput of Philadelphia, Joseph E. Kurtz of Louisville, Kentucky, the USCCB president, and William E. Lori of Baltimore.

The Knights of Columbus and In Defense of Christians also released a 300-page report to the U.S. State Department which was instrumental in the genocide declaration. The report documented the atrocities and personal accounts of sexual slavery, murder and assassinations of Church leaders and other violence committed against Christians by the Islamic State.

Carl Anderson, Supreme Knight of the Knights of Columbus, called the move a historic call to action for both the U.S. government and the international community.

“By joining its voice to that of the House of Representatives, the American people, and the international community, the United States today makes clear to ISIS that its attempt to stamp out religious minorities must cease,” Anderson said in response to the announcement.

In Defense of Christians said the declaration was an important step in raising international awareness of the situation and a compelling call to action for “responsible nations to act.”

“By proclaiming that they are victims of genocide, the United States has done a great justice to the victims of the atrocities committed by ISIS, including the over 1,100 Christians who have been killed because of their faith,” the statement continued. “Hearing the voice of the United States speak this truth will restore the hope in the hearts of those who are still fearing for their lives and struggling to survive in the Middle East.”

The website for the “Stop the Christian Genocide” petition noted that while the declaration is important, Christians in the Middle East still need help. Those interested in providing assistance can visit the “Christians at Risk” page from the Knights of Columbus: www.kofc.org/en/christianRelief/index.html, and the website for In Defense of Christians, which includes the report presented to the State Department: indefenseofchristians.org.