"You know well how a lack of mutual knowledge (between people) is a source of so many misunderstandings and sometimes even clashes," he said in written remarks to a group of bishops, who were making their "ad limina" visits to the Vatican March 1-8.

The visits to report on the state of their dioceses brought together members of the regional conference of Catholic bishops from North Africa: Algeria, Libya, Morocco, and Tunisia.

After meeting the bishops March 2, Pope Francis said the region has undergone some major developments that have increased people's hopes for "greater freedom, dignity and the promotion of greater freedom of conscience."

However, he noted the movement also brought with it "explosions of violence." Islamic State militants murdered 21 Christians in Libya in late February.

The Pope said he wished "to pay homage to the courage, trust and perseverance" of the bishops, religious and lay Catholics who stayed in the Libya despite the many dangers there.

Calling them "authentic witnesses of the Gospel," he offered his gratitude and encouraged them to continue "to contribute to peace and reconciliation throughout your region."

Pope Francis told the bishops that interreligious dialogue was an important part of the church's life in the mostly Muslim region.

He cited Pope Benedict XVI's post-synodal apostolic exhortation, "Africae Munus," saying, "If all of us who believe in God desire to promote reconciliation, justice and peace, we must work together to banish every form of discrimination, intolerance and religious fundamentalism."

"The most effective antidote to every form of violence is education about the discovery and acceptance of difference as something rich and fruitful," Pope Francis said, and he asked that religious and lay Catholics receive formation in this field, calling it "indispensible."

The church is about "encounter and dialogue" as well as service to everyone in need "without distinctions." He praised the way they did charitable work, "often with humble means," among the poor, the sick, the elderly, women and prisoners.

"You are 'in the peripheries' with the unique service of showing Christ's presence in his church in this region," he said, adding that their life of simplicity and poverty was "an important sign for the whole church."

The Pope said he would be accompanying them with his prayers as they continue their "difficult journey," and he encouraged the bishops "to always be men of hope."

Archbishop Ilario Antoniazzi of Tunis told Vatican Radio that the Pope encouraged them to stay in the countries they serve, telling them that "your prayers, your suffering, which is your life's witness, is much more important than any words you can say because Christ acts not through your words but through your life."

"Perhaps we cannot speak very much, but our witness and our charity are the most beautiful testimony and the most beautiful kind of preaching we can give," said the 66-year-old Italian-born archbishop.

The Muslim community in Tunis is very "peaceful," he said, and residents recognize the important work the church does, especially with their schools and local Caritas.

Interreligious dialogue and joint initiatives help because "it is very important to get to know each other," he said. "We have to be familiar with Islam because there are people who are truly lovely, who want peace, who collaborate with us."

Letting fear have the upper hand, he said, "is the worst thing we can do."

The archbishop said many of the Catholics the region's bishops minister to are on the move -- foreign students and workers who are in Tunisia only temporarily.

"What impresses us most," he said, is that when those Christians return to their home country "they say: 'We learned so much and we return richer in our Christianity because we lived with a people who were also Muslim, who practiced their faith, who are committed in their faith in one God, like us, and they taught us so much about putting God at the center of our life.'"