Catholics across the country reflected on the tragedy of 9/11 as Americans observed the 21st anniversary of the terror attacks that shook the world and the nation.

“May we continue to seek consolation in the Lord, an end to terrorism in all forms, and gratitude for the first responders on the morning of September 11, 2001. Our Lady of Sorrows, pray for us,” the Archdiocese of St. Paul & Minneapolis said in a tweet.

Similar messages were put out by other Church leaders, with some dioceses celebrating with remembrance Masses.

“Dear police officers, firefighters, sheriffs and park rangers of our city of San Francisco: It is an honor for us to host you here… for this Mass in which we thank you for the sacrifices you make for us, sacrifices mostly which we do not even see,” Archbishop Salvatore Cordileone tweeted Sunday.

The U.S. Conference of Catholic Bishops (USCCB), as it has done before, also addressed the topic.

“As we remember Sept. 11, 2001, let us reflect on Pope Francis' Prayer of Remembrance at Ground Zero in 2015,” the USCCB tweeted. The tweet included an excerpt from Pope Francis’ prayer from the Ground Zero Memorial during his visit to New York in September, 2015.  That prayer can be read in full here.

The attacks on the World Trade Center and the Pentagon were a subject of prayer and pastoral messages from the outset, with the USCCB making one of the first widely spread messages.

The USCCB released a pastoral message titled “Living With Faith and Hope After September 11”  two months after the attacks. The bishops quote the Beatitudes (Mt. 5:4,6,7,9) in it, and said, “We offer words of consolation, criteria for moral discernment, and a call to action and solidarity in these troubling and challenging times.”

In that message, the bishops honored the firefighters, law enforcement officers, chaplains and others who died during the attacks or in the aftermath. The document focuses on responding with faith and justice and reminds readers to understand the role that religion can play in politics and terrorism. The USCCB emphasized the nation’s commitment to the common good, in unity with a determination to come together and defend America from all future threats, the pastoral message says.

Last year, the Pillar released “The Catholic Church and 9/11,” an article documenting stories and testimonials from that day. Pope St. John Paul II addressed the attacks on Sept. 12, 2002, saying, “Christ’s word is the only one that can give a response to the questions which trouble our spirit. Even if the forces of darkness appear to prevail, those who believe in God know that evil and death do not have the final say,” the Pillar article says.

In 2011, a prayer service was held at St. Patrick’s Cathedral in New York City, in which a Brooklyn pastor said, “We decided to have exposition of the Blessed Sacrament. People flocked to the church… We held many funerals for police and fire persons who gave their lives,” the Pillar article adds.

Other Church leaders have given unique perspectives on the attacks, with Father Brian Jordan, a Franciscan Friar, telling the story of the Ground Zero Cross that survived the attack despite being in the middle of so much carnage in a video.