After offering prayers for the victims of the Sep 11 terror attacks at Ground Zero, Pope Benedict XVI celebrated Mass for a crowd of about 57,000 people at Yankee Stadium Sunday.

The Mass at the stadium was his last official public appearance in of a six-day visit to the US on what he described as a pilgrimage of peace and justice.

A special throne with the papal seal was erected for Benedict above second base of the packed baseball stadium while nearly 600 priests and deacons occupied rows of seats along the sides of the diamond-shaped field.

A 58-member orchestra led by New York Metropolitan Opera tenors also sang during the Mass with New York Mayor Michael Bloomberg and dozens of cardinals and other US church officials in attendance.

On his final day in the US, Benedict visited Ground Zero early Sunday and knelt alone to offer a silent prayer for the 3,000 people killed in the terrorist attacks against the US Sep 11, 2001.

Extraordinary security measures were mounted to protect the pope at one of most sensitive sites in the city, where the World Trade Center towers were felled by suicide hijackers.

A group of 24 people representing families of the victims were present at the ceremony at Ground Zero, where the Benedict lit a single candle to commemorate the dead.

At Yankee Stadium, all attendees had received tickets from their local churches throughout the US to take part in the mass.

Benedict said in his homily that his celebration Sunday was a "sign of the impressive growth which God has given to the church in your country in the past 200 years."

He said that the Catholic Church in the US grew from a small number of people "built up in fidelity to the twin commandment of love of God and love of neighbour. In this land of freedom and opportunity, the church has united a widely diverse flock in the profession of the faith and, through her many educational, charitable and social works, has also contributed significantly to the growth of American society as a whole."

The US church was established by immigrants from Europe, first in Baltimore and then in New York, Boston, Philadelphia and other cities as the population moved west.

"In this land of religious liberty, Catholics found freedom not only to practice their faith but also to participate fully in civic life, bringing their deepest moral convictions to the public square and cooperating with their neighbours in shaping a vibrant, democratic society," the pontiff said.

He urged US Catholics to use the freedoms they enjoy to build for future generations.

Benedict read the last part of his homily in Spanish in an obvious gesture to the large and growing community of Latino Catholics in the US, many of whom attended rallies to greet him.