Pope Francis, Jesuit priest who is called "The People's Pope," addressed the Charlie Hebdo attack while in his way to his stop in The Philippines. The Pope said freedom of expression has limits when it insults or ridicules religions.

Pope Francis defended free speech as a fundamental human right, saying that it is a person's duty to speak one's mind for the common good, but the recent terror attacks in Paris show the limits.

Satirical magazine Charlie Hebdo published inflammatory cartoons of the Prophet Muhammed. Islamic extremists attacked the magazine's Paris offices. Gunmen then attacked a kosher supermarket. 17 people died in the attacks.

Pope Francis has been satirized in Charlie Hebdo.

The Vatican issued a joint declaration with four prominent French imams denouncing the Charlie Hebdo attacks. Pope Francis urged Muslim leaders to speak out against Islamic extremism, saying it is an "aberration" to kill in the name of God.

The Pope referred to papal trip organizer Alberto Gasparri.

"If my good friend Dr. Gasparri says a curse word against my mother, he can expect a punch. It's normal. You cannot provoke. You cannot insult the faith of others. You cannot make fun of the faith of others," Pope Francis said.

 "One cannot provoke, one cannot insult other people's faith, one cannot make fun of faith," Francis said. He added that every religion "has its dignity."

The Pope said if his "great friend says a swear word against my mother, then he is going to get a punch. But it's normal, it's normal." But added that "one cannot offend, make war, kill in the name of one's own religion, that is, in the name of God."

Charlie Hebdo published a record 3 million copies of its new edition in the wake of the attack. The cover shows the Prophet Mohamed crying.

"There are so many people who speak badly about religions or other religions, who make fun of them, who make a game out of the religions of others. They are provocateurs. And what happens to them is what would happen to Dr. Gasparri if he says a curse word against my mother. There is a limit," the Pope said.

The Vatican says it has received no specific threats since the Charlie Hebdo massacre, but Francis said Vatican security officials are taking "prudent and secure measures."

"I am worried, but you know I have a defect: a good dose of carelessness. I'm careless about these things," the Pope said.  But admitted " I'm not very courageous when it comes to pain. I'm very timid."

"I'm in God's hands," he added.