SAO PAULO, Brazil — Pope Benedict XVI began his first trip to Latin America yesterday by laying down church law on abortion, suggesting that he agrees with bishops who said Catholic politicians in Mexico had excommunicated themselves by legalizing abortion in that nation’s capital.

Benedict also spoke strongly against abortion during his first speech in Brazil.

Speaking in Portuguese, he said he’s certain that the bishops will reinforce “the promotion of respect for life from the moment of conception until natural death as an integral requirement of human nature.”

Hundreds of faithful waiting in the rain for a glimpse of Benedict. The Vatican says the pope hopes to confront during his visit, such as the church’s declining influence in Brazil, the rise of evangelism, or his in-flight comments about Mexico City’s politicians.

Catholic officials have been debating for some time whether politicians who approve abortion legislation as well as doctors and nurses who take part in abortions would subject themselves to automatic excommunication under church law.

The pope seemed to agree with Mexico City’s bishops who declared that the city’s pro-abortion lawmakers had excommunicated themselves.

“It’s nothing new, it’s normal, it wasn’t arbitrary. It is what is foreseen by the church’s doctrine,” Benedict told reporters aboard a plane to Brazil.

In a statement approved by the pope, Benedict’s spokesman, the Reverend Federico Lombardi, said the pontiff did not intend to formally excommunicate anyone — a separate and rare process under church law. “Since excommunication hasn’t been declared by the Mexican bishops, the pope has no intention himself of declaring it,” said Father Lombardi, who was on board the plane.

But Father Lombardi said politicians who vote in favor of abortion should not receive Holy Communion. “Legislative action in favor of abortion is incompatible with participation in the Eucharist. … Politicians exclude themselves from Communion.”

Pressed on whether the lawmakers were excommunicated, Father Lombardi reiterated: “No, they exclude themselves from Communion.”