An American missionary carrying a letter for the North Korean dictator crossed illegally into the reclusive country to try bring international attention to the North Korean suffering, South Korean activists said Saturday.

"I am an American citizen," Robert Park, 28, said as he crossed the frozen river separating China from North Korea on Friday, according to Jo Sung-rae, head of Pax Koreana, a conservative civic group based in Seoul. "I am coming here to deliver God's love. God loves you."

By early Sunday, there was no word of his fate from North Korea.

Before heading to China last week to make the journey, Mr. Park said he was determined to become a "martyr" for the tens of thousands of people said to be incarcerated in North Korea's infamous concentration camps, Mr. Jo said.

In a videotaped message he made before the trip, Mr. Park said he wanted to be arrested and had no intention of leaving North Korea voluntarily until it shuts down its camps. He also said he did not want President Obama to "buy his freedom."