Pope Benedict, celebrating a stadium Mass for 45,000 people, acknowledged on Thursday that the U.S. pedophile priests scandal caused "indescribable pain and harm" to victims but asked Catholics to love their pastors.

For the third consecutive day of his trip to the United States, Benedict mentioned the scandal that rocked the Church in 2002 and cost U.S. dioceses $2 billion in damages, demonstrating his resolve to deal with the issue and make sure it does not happen again.

"No words of mine can describe the pain and harm inflicted by such abuse," he said in the sermon of a Mass at Nationals Park, a new stadium hosting its first non-baseball event. Advertisements flanking the scoreboard were covered by U.S flags.

A large yellow and white papal flag fluttered in left field and a papal seal covered home plate as the pope said Mass from an altar platform in center field. Benedict, who arrived in Washington on Tuesday on his first visit to the United States as pontiff, said the Mass as music from cultures and languages of America's melting pot played. "It is important that those who have suffered be given loving pastoral attention. Nor can I adequately describe the damage that has occurred within the community of the Church," he said during Mass.

But he said great efforts had been made to deal "honestly and fairly" with the aftermath of the scandal, which broke when it was discovered that priests who had abused children were transferred instead of being defrocked or turned over to police.

Speaking from a towering white and gold altar platform, the Pope asked U.S. Catholics to foster healing and reconciliation with victims and added: "Also, I ask you to love your priests, and to affirm them in the excellent work that they do."

The Church's position has always been that an extremely small number of priests -- less than one percent -- were abusers while the overwhelming majority were faithful to their vocation and protected children.

The Survivors Network of those Abused by Priests, issued a statement before the Mass, saying they wanted more action from the Pope. "Despite twice making brief remarks about the church's on-going child sex abuse and cover up scandal, we've still seen no action. Not one child is safer today because of what the pope said," said Barbara Dorris of SNAP. Bill Fay, a Catholic from Rockville, Maryland who attended the Mass, said the scandal had not shaken his faith and that he decided to keep his children in Catholic schools. But he was critical of the way the Church handled the crisis.

"They did a fairly good job of attempting to sweep it under the rug," he told Reuters at the Mass. The Mass gave Washington a chance to show off its new $611-million baseball field, which opened two weeks ago. Some 300 hundred priests were on hand to distribute communion to tens of thousands of faithful in 20 minutes.

The Mass included four choirs totaling 570 singers. Opera star Placido Domingo, general director of the Washington National Opera, sang "Panis Angelicus" in Latin and at the end of the Mass the Pope went into the crowd to shake hands.

In his sermon the Pope, who wore red, white and gold vestments, again praised U.S. society but said not everyone had gotten a piece of the American dream in the past. "

To be sure, this promise was not experienced by all the inhabitants of this land; one thinks of the injustices endured by the native American peoples and by those brought here forcibly from Africa as slaves," he said. He also lamented "clear signs of a disturbing breakdown in the very foundations of society: signs of alienation, anger and polarization on the part of many of our contemporaries; increased violence; a weakening of the moral sense; a coarsening of social relations and a growing forgetfulness of God."

Later on Thursday the Pope, who turned 81 on Wednesday and was feted at the White House, will address heads of Catholic universities and schools and meet leaders of other religions. He goes to New York on Friday to address the United Nations. He returns to Rome on Sunday after visiting the site where the World Trade Center was destroyed in the hijacked plane attacks of Sept. 11, 2001, and saying Mass at Yankee Stadium.