Not everyone will welcome the Pope to South Korea.

A group of Protestants held a demonstration on Tuesday, slamming the Roman Catholic Church as heretical.

Organizers say about 10,000 people attended the event at a convention center west of Seoul, where a number of Protestant pastors stressed the difference between the Roman Catholic Church and Protestant churches, according to local Protestant media.

Rev. Song Chun-gil, the secretary general of the group, called Catholicism a perversion of faith, according to the reports. He has opposed recent moves among mainstream Protestant church leaders to form a relationship with the Roman Catholics, according to local media. (The Christian Daily has photos from the event.)

South Korea's Protestant churches, divided into different alliances and denominations, haven't issued a unified position on the Pope's visit, which begins on Thursday.