Pope Francis urged South Koreans, among Asia's richest people, to beware of the spiritual "cancer" that often accompanies affluent societies, as he led a Mass on Friday to commemorate the more than 300 people killed in a ferry disaster in April.

Tens of thousands of Asian Catholics gave a boisterous welcome to the pope as he celebrated his first public Mass in South Korea, a country with a small but growing church that is seen by the Vatican as a model for the rest of the world.

Francis took a high-speed train to the central city of Daejeon, where Catholic youths from across Asia have been meeting for the Asian version of World Youth Day.

Hundreds of trees were decked with yellow ribbons in the city in remembrance of the mostly school children who died when the Sewol ferry sank.

In the homily of the Mass, the pope urged listeners to "combat the allure of a materialism that stifles authentic spiritual and cultural values and the spirit of unbridled competition which generates selfishness and strife".

He said they should see their faith as an "antidote to the spirit of despair that seems to grow like a cancer in societies which are outwardly affluent, yet often experience inner sadness and emptiness".

Catholic numbers growing

Francis celebrated Mass in Daejeon's soccer stadium, which has a capacity of 50,000 and was nearly full hours before Francis arrived.

Handkerchief-waving crowds led in chants of "Viva il papa!" welcomed him as his open-sided vehicle, with a simple canopy overhead, made its way slowly to the stadium and then inside.

A banner outside the stadium featured a photo of the pope and read "Please wipe the tears of the Sewol families.''

After Mass, Francis was to eat lunch with some of the youth festival participants and then visit an 18th century sanctuary where Korea's first priest was raised.

South Korean Catholics represent only about 10 percent of the country's 50 million people, but their numbers are growing. Once a country that welcomed missionaries, South Korea now sends homegrown priests and nuns abroad to help spread the faith.

Source: Al Jazeera and agencies