Scores of South Koreans rallied Seoul in support of human rights activist Robert Park, a Korean-American who crossed into North Korea on his own from China last week.
The demonstrators were mainly conservative elderly men who belong to Christian churches in Seoul, but they hope to be the start of an international groundswell.
Colleagues say Park, a devout Christian, crossed into North Korea on Christmas Day with a letter exhorting leader Kim Jong Il to close down concentration camps, and allow impoverished North Koreans access to outside aid.
A rally leader yells, "He crossed over the frozen Tumen River and shouted loudly and boldly that he had come to deliver God's love."
Activist Jo Sung-rae has known Park for about 10 years. He says Park planned his action by himself, but Jo offers his support. He says this is the first time the Gospel has entered North Korean territory in this way in 60 years.
Pyongyang has occasionally allowed Christian missionaries to visit, but only under tightly controlled conditions.
Jo says Park entered North Korea exactly on the 25th - Christmas Day - with God's message. North Korea is claiming the date was the 24th. He says that shows that North Korea is really scared about this incident.
Rally leader Seo Seok-gu says he expects that fear will lead North Korea to deport Park very soon.
He says all the world's conscience is focused on North Korea's next move in the Park case. If the North treats him harshly, he says, there will be a strong global media backlash. So, he says, North Korea will probably deport him.
Park said in a recent interview he is willing to be executed if it will spur international governments to action on North Korean human rights.