On any papal visit, security is a top concern. Throughout history, more than two dozen popes have been murdered.

Pope Benedict XVI waves as he boards a plane on his way to Mexico and Cuba on March 23. (FILIPPO MONTEFORTE/AFP/GETTY IMAGES)

The Mexican branch of hacktivist collective Anonymous has blocked at least two Web sites for the pontiff’s visit, the Associated Press reports. In a video, the hackers called the pope’s visit a political ploy, designed to dredge up support for Mexico’s conservative National Action party ahead of the July presidential election. The group also accused the visit of costing Mexicans money that would be better spent on the poor.

Two weeks ago, the Vatican’s Web site also went offline, which Anonymous said was their handiwork. The Vatican insisted the issue was a “technical problem that's being solved.” The site is now back up.

The pope is unlikely to see any signs of political unrest in Cuba, where the government has begun cracking down on demonstrations ahead of his visit. The Cuban government has arrested more than 70 members of the Ladies in White, a Cuban opposition movement made up of wives and other female relatives of jailed dissidents, and has removed dissidents who were occupying a church in central Havana.