Updated

Missionaries in northeastern China are engaged in a dangerous work: spreading Christianity across the border to North Korea.

A South Korean pastor says at least 10 missionaries and pastors have died mysteriously in recent years and suspects North Korea is to blame. Hundreds of others have been imprisoned and expelled from China, which bans foreigners from proselytizing.

Some keep at it in part because they believe their converts could help change religious practice in the cloistered North, which equates Christianity with U.S.-led Western imperialism.

The border missionaries provide their North Korean visitors with room and board, and those escaping with places to hide. In return, they ask them to memorize Christian prayers and covertly share what they've learned when they return home.