Following his historic 12-day trip to Southeast Asia, Pope Francis chimed in on the upcoming U.S. presidential election, instructing U.S. Catholics to use their “conscience” when voting and to choose the “lesser evil.”

“Both are against life,” the pope told reporters on Friday during a 42-minute news conference on the papal plane as he returned to the Vatican from Singapore. “Both are against life. Both.”

Vice President Kamala Harris supports expanding access to abortion, while former President Donald Trump has said, if elected, that he planned to deport 11 million undocumented migrants.

Catholic teaching says that abortion is a sin and that mistreating migrants is an assault on human dignity. Popes are also not known for making political endorsements.

“The one who throws out migrants and the one who kills children. Both are against life,” Pope Francis said of Harris and Trump.

In answering the question regarding the election, the pontiff — born in Argentina to Italian immigrant parents — opened by addressing the ongoing migrant crisis, saying, “To send migrants away or to not give migrants the ability to work, to not give migrants a welcome, is serious. It is a sin.”

Francis then turned his attention to abortion.

“Science says that a month after conception all of the organs of a human being are there,” he said. “All of them.”

He added that abortion “is to kill a human being.”

“You may like the word, or you don’t like it, but it is to kill. … To send away a child from the womb of the mother is an assassination because there is life,” he said.

The pope’s remarks came three days after the very first debate between Harris and Trump, which featured a series of heated exchanges on issues that included abortion and immigration. This year’s presidential election is the first since the Supreme Court overturned Roe v. Wade two years ago, pushing the issue back to the states.

Nonetheless, Francis said Catholics “have to vote” come Nov. 5.

“In political morality, in general they say that if you don’t vote, it’s not good, it’s bad,” he said. “You have to vote, and you have to choose the lesser evil. What is the lesser evil — that woman [Harris] or that man [Trump]? I don’t know. Each one, in their conscience, must think.”

Earlier this week, a poll by Pew Research Center revealed that a slim majority of U.S. Catholics intend to cast their ballot for Trump.

Among Catholics overall, 52 percent said they were backing Trump this year, compared with 47 percent who said they preferred Harris. Trump’s support, meanwhile, rose to 61 percent among white Catholics, while Harris garnered 65 percent from Hispanic Catholics.

 Produced in association with Religion Unplugged