"My reaction was, 'Why not?' We have shared values and there is a possibility of collaboration on a number of social issues while respecting our theological differences," he said.
Father Massa said, "We're not making any theological statements today," adding, "This is a very big statement they (the Latter-day Saints) are making."
He said the Latter-day Saints are "a bit bruised" by reaction to the presidential campaign of Republican Mitt Romney, a Mormon. National polls found that many Americans were uncomfortable with the idea of a Mormon president.
Representing the Latter-day Saints at the April 18 meeting in New York were two members of the Quorum of the Twelve Apostles, Elders M. Russell Ballard and Quentin L. Cook.
Father Massa described the request as coming out of a growing respect between Catholics and Mormons, which began under the leadership of the late Gordon B. Hinckley, longtime president of the Latter-day Saints.
During Hinckley's 13-year tenure as president, he met with the current and former bishops of Salt Lake City. And Chicago Cardinal Francis E. George, president of the U.S. Conference of Catholic Bishops, sent condolences when Hinckley died in January.
"I think these developments have prepared us to begin a new phase in our relationship," Father Massa said.
Although media representatives of the Latter-day Saints did not respond to a request for comment on the papal prayer service April 18, a statement on "respect for diversity of faiths" was posted on the church's Web site the same day as the New York meeting.
"Members of the (Latter-day Saints) church do not view fellow believers around the world as adversaries or competitors, but as partners in the many causes for good in the world," the statement said, noting the church's cooperation with Catholic Relief Services in efforts to assist victims of famine and natural disasters.
CRS is the U.S. bishops' overseas relief and development agency.
"It is important to note that interfaith cooperation does not require doctrinal compromise," the statement added. "It is necessary to maintain a separation between charitable efforts and doctrinal tenets, while at the same time sharing a mutual concern for those in need.
"People of good faith do not need to have the exact same beliefs in order to accomplish great things in the service of their fellow human beings." it said.
In recent years the Mormon church sometimes has joined Catholic officials in initiatives both churches supported, such as opposition to same-sex marriage.
However, a Vatican ruling in 2001 that required Mormons who became Catholics to receive a full baptism rather than a conditional one was seen by some as questioning whether members of the Church of Jesus Christ of Latter-day Saints were Christians.
But then-Bishop George H. Neiderauer, who headed the Salt Lake City Diocese at that time, said the Vatican decision "should not be understood as either judging or measuring a spiritual relationship between Jesus Christ and the LDS church."
"As we know, the LDS church baptizes all its new members who were previously baptized in any other church," said Bishop Neiderauer, who is now archbishop of San Francisco. "That practice indicated that the LDS church regards its own baptism as accomplishing something which is substantially different from that of all other baptismal rites."
The Vatican ruling, he said, "indicates that the Catholic Church also recognizes that LDS baptism is substantially different from Roman Catholic baptism."
The Vatican commentary on the ruling called for continued Catholic-Mormon cooperation, dialogue and growth in understanding.
Contributing to this story was Nancy Frazier O'Brien in Washington.