SAO PAULO, Brazil (AP) – As if Pope Benedict XVI did not face enough challenges on his first papal visit to Latin America, his comments on abortion during an in-flight news conference Wednesday had Vatican officials scrambling to clarify what he meant to say before his plane even set down in Brazil.

Benedict’s trip to the region where half the world’s 1.1 billion Catholics live comes at a critical time. The church is losing members to a booming evangelical Protestant movement, and the pontiff plans to speak forcefully against crime, poverty and moral relativism during his five-day visit.

But it was his response to a reporter’s question about the politicians who legalized abortion in Mexico City that had Catholic scholars and Vatican officials scrambling to sort out the fine points of church doctrine before his Alitalia jet touched down in Sao Paulo.

In his first full-fledged news conference, the pope was asked whether he agrees with Mexican bishops that the Catholic politicians who voted for abortion should rightfully be considered excommunicated and he replied, “Yes.”

“The excommunication was not something arbitrary,” Benedict continued. “It is part of the (canon law) code. It is based simply on the principle that the killing of an innocent human child is incompatible with going in Communion with the body of Christ. Thus, they (the bishops) didn’t do anything new or anything surprising. Or arbitrary.”

Catholic scholars pounced. Church officials have been debating for some time whether politicians who approve abortion legislation as well as doctors and nurses who take part in the procedure subject themselves to automatic excommunication under church law. And Benedict’s statement seemed to come down firmly on the side of excommunication.

The Rev. John Coughlin, a law professor at the University of Notre Dame, said there is no provision in canon law supporting the Mexican bishops’ position that Catholic politicians who vote to legalize abortion automatically excommunicate themselves.

Vatican officials later said the pope might have mistakenly inferred from the way the reporter phrased the question that the Mexican bishops had issued a formal declaration of excommunication for the legislators. But Mexican Cardinal Norberto Rivera has publicly said he has no intention of doing that.

Benedict’s spokesman, the Rev. Federico Lombardi, quickly issued a statement approved by the pope saying he was not setting a new policy and did not intend to formally excommunicate anyone – a rare process under church law that is separate from the doctrine of self-excommunication.

But Lombardi added that the sacrament of Holy Communion should be denied to pro-abortion politicians. “Legislative action in favor of abortion is incompatible with participation in the Eucharist. … Politicians exclude themselves from Communion,” he said.

It was not the first time Benedict has appeared to speak directly, only to backtrack or refine his original statement. The most controversial example occurred when he raised the issue of Islam and violence, and anger spread across the Islamic world. Benedict later said he meant no offense, but he has never again pointed the finger at Muslims while condemning religious violence.

This pope’s apparent candor can get him in trouble, said John L. Allen Jr., a reporter with the National Catholic Reporter. “Benedict doesn’t seem to distinguish when he is speaking as Cardinal Joseph Ratzinger and when he is speaking as the head of the Roman Catholic Church.”

Benedict himself seemed to take it in stride on Wednesday, acknowledging that many people neither agree with him, nor listen to his teachings.

“In all parts of the world, there are those who don’t want to hear,” Benedict said on the plane. “Naturally, even our Lord did not manage to make everyone hear.”

Later, he was joyfully received by thousands of Catholics who waited in the cold rain for a glimpse of Benedict at the monastery where his is staying. Chanting “Bento, Bento” (Portuguese for Benedict), they waved flags of different South American nations as he blessed them.

“The pope is the representative of Christ on Earth and I’m emotional about meeting him,” said Marcelo Zapata, a university student who flew in from Chile to see the pontiff.

Shivering in the cold, Edmundo Barbosa, a 32-year-old salesman, said, “I just want to see what he looks like, and if I could talk to him I’d ask for peace.”