On the eleventh anniversary of the worst terrorist attacks the U.S. has seen, Church leaders and political figures remembered those who lost their lives and offered prayers for the nation's future.

"This 9/11, let us pray for those souls who died that sad day," tweeted Cardinal Timothy M. Dolan of New York. "Eternal rest grant unto them, O Lord, and let perpetual light shine upon them."

Crowds gathered at the site of the World Trade Center in New York City, the Pentagon just outside Washington, D.C., and Shanksville, Pa., to remember those who died there in the terrorist attacks on Sept. 11, 2001.

"On the anniversary of 9/11, we invite to you pray for all those who lost their lives, for their loved ones and for the courage to build a culture of true peace and love," the Archdiocese of Washington, D.C. said on its Facebook page.

The archdiocese also commemorated the day on Twitter by calling to mind the beatitude, "Blessed are they who mourn, for they will be comforted."

In addition, it recalled that Fr. Mychal Judge, an NYFD chaplain, was the first recorded fatality on that day. He died at the World Trade Center, offering aid and prayers to victims and rescuers.

"May God bless Fr. Mychal Judge," the archdiocese tweeted, pointing to Christ's words that "Greater love hath no man than this, that a man lay down his life for his."

The archdiocese of Washington, D.C. also posted a link to the U.S. bishops' pastoral message, "Living With Faith and Hope After September 11," which was released in November, 2001.

In that message, the bishops recognized the fundamental challenges facing America.

"Our nation has a right and duty to respond and must do so in right ways, seeking to defend the common good and build a more just and peaceful world," they said.

"Our community of faith has the responsibility to live out in our time the challenges of Jesus in the Beatitudes," they added, calling on the faithful to approach these duties "with faith and hope, asking God to protect and guide us as we seek to live out the Gospel of Jesus Christ in these days of trial."

The eleventh anniversary of the 9/11 tragedy united Americans in the midst of intense debates about the future of the nation. And in the final weeks of a heated election season, politicians paused from their campaigns to reflect on the occasion.

President Barack Obama proclaimed Sept. 7-9 as National Days of Prayer and Remembrance.

"On these days of prayer and remembrance, we mourn again the men, women, and children who were taken from us with terrible swiftness, stand with their friends and family, honor the courageous patriots who responded in our country's moment of need, and, with God's grace, rededicate ourselves to a spirit of unity and renewal," he said in the proclamation.

Both Obama and Republican presidential candidate Mitt Romney suspended their negative ads for the day out of respect for the victims of the 2001 tragedy.

"On this most somber day, those who would attack us should know that we are united, one nation under God, in our determination to stop them and to stand tall for peace and freedom at home and across the world," Romney said in a statement.

Congressional leaders from both parties spoke at a Congressional Remembrance Ceremony on the steps of the Capitol, which included prayer and patriotic songs.  

Church communities and leaders across the country also reflected on the occasion and offered their continued prayers for all those who were affected.

"Praying for the victims and survivors of 9/11 attacks," the Archdiocese of New Orleans posted on Twitter.

"Remember this day all those whose lives were taken. Keep their families in your prayers," tweeted Bishop Curtis J. Guillory of Beaumont, Texas.