ANDREWS AIR FORCE BASE, Md.
Pope Benedict XVI arrived Tuesday in the United States to a presidential handshake and enthusiastic cheering, a warm welcome that followed the pontiff's candid admission hours earlier that he is "deeply ashamed" of the clergy sex abuse scandal that has rocked the American church.

On his first papal trip to the U.S., Benedict gave hundreds of spectators a two-handed wave as he stepped off a special Alitalia airliner that brought him from Rome. Students from a local Catholic school screamed ecstatically when the saw the pontiff, who shook hands with President Bush, first lady Laura Bush and their daughter, Jenna on the tarmac.

The pope and the president left in a motorcade a few minutes later.

About 400 people filled stands on the tarmac at the base, cheering his arrival. Among them are about 100 parishioners from area Catholic churches. Many of them said they won lotteries for the chance to see Benedict arrive.

Imelda Laforteza, 38, who goes to St. Peter's Catholic Church in Waldorf said his visit is "a blessing for all of America."

On the flight to the United States from Rome, Benedict addressed the most painful issue for the Roman Catholic Church in America clergy sex abuse. The U.S. church has paid out $2 billion in abuse costs since 1950, most of that in just the last six years.

"It is a great suffering for the church in the United States and for the church in general and for me personally that this could happen," Benedict said. "It is difficult for me to understand how it was possible that priests betray in this way their mission ... to these children."

"I am deeply ashamed, and we will do what is possible so this cannot happen again in the future," the pope said on the flight from Rome to Washington, speaking in English as he responded to questions submitted by reporters ahead of time.

Benedict pledged that pedophiles would not be priests in the Catholic Church.

"We will absolutely exclude pedophiles from the sacred ministry," Benedict said. "It is more important to have good priests than many priests. We will do everything possible to heal this wound."

The pope's promise failed to mollify advocates for abuse victims, however. They said the problem is not just molester priests, but bishops and other church authorities who have let errant clergymen continue to serve even after repeated allegations.

"It's easy and tempting to continually focus on the pedophile priests themselves," said Peter Isely, a board member of the Survivors Network of those Abused by Priests. "It's harder but crucial to focus on the broader problem complicity in the rest of the church hierarchy."