Pope Francis delivered a mass to tens of thousands of South Korean youths, urging them to renounce the materialism that afflicts much of Asia and reject what he called "inhuman" economic systems that disenfranchise the poor.
The pope spoke Friday at a soccer stadium in the city of Daejeon that seats 50,000 people. It was his first public appearance since arriving in Seoul on Thursday. Before the mass, Pope Francis met with families of victims and some survivors of the Sewol ferry disaster in April.
Upon arriving on Thursday, Francis met with South Korean President Park Geun-hye and the two leaders gave a joint address.
Speaking in English -- a rarity for the Spanish-speaking pope -- Francis said diplomacy is based on dialogue, rather than accusations and threats, and noted that Korea's "quest for peace" affects the stability of the entire region.
President Park said North and South Korea should get rid of fear and nuclear weapons and concentrate on reunification.
She thanked the pope for his prayers and for carrying out a mass "for peace and reconciliation" during his visit.
As Pope Francis's plane was landing in Seoul, North Korea fired the first of five projectiles into the Sea of Japan.
Foreign Ministry spokesman Noh Kwang-il condemned the launches, which are the latest in a series of similar rocket tests by the North.
The North declined to send a delegation to the papal mass, citing its anger at upcoming U.S.-South Korean military drills.
Like all other religions in North Korea, Catholicism is allowed to exist only under the tightest of restrictions. As a result, it is unclear how many North Koreans practice Catholicism.
The pope's trip to South Korea is also highlighting tensions between the Vatican and China, which do not have diplomatic relations.
As his plane flew over Chinese airspace, Pope Francis sent a message to President Xi Jinping offering "divine blessings of peace and well-being upon the nation."
Despite the Vatican's objections, Beijing insists on maintaining a state-controlled Catholic church that does not answer to Rome. There is also a large underground church, and the two sides disagree over which has the authority to ordain priests.
About 100 Chinese had planned to attend the Asian Youth Day but on Thursday Heo Young-yeop, a spokesman for the papal visit to Korea, said half of those had been unable to attend.
Chinese officials have not commented on why the youths were unable to attend.
South Korea boasts about five million Catholics and is one of the church's fastest growing congregations in the world.
Francis’ trip is the first to the nation since Pope John Paul II visited South Korea in 1989. Vatican officials say Francis will bring a message about the "future of Asia" and speak to all countries on the continent during his trip.