HAVANA - Pope Francis says his deepest desire for his trip to Mexico is to simply pray before the shrine of the Virgin of Guadalupe.

Speaking to reporters en route to his first stop in Havana, Francis said he knew that the Virgin is beloved to Catholics and even those who are not.

"This mystery that they study, study, and there are no human explanations," he said. "The most scientific study says this is something of God. This is what I'll tell the Mexicans, even those who say 'I'm atheist but I'm a Guadalupeno.' - Then he corrected himself: "Some Mexicans. Not all are atheists."

Francis arrives in Mexico Friday night and he's due to celebrate Mass in the Basilica of Guadalupe on Saturday evening. The trip to Mexico runs through Wednesday.