A Seoul-based human rights group says North Korea has executed 70 defectors who were captured in China and repatriated.
The private Commission to Help North Korean Refugees cited informants in the North as saying the executions were carried out to set an example for others thinking about fleeing.
The group said in a statement Friday that eight or nine defectors were executed last month in public to discourage other people from fleeing to China.
South Korean officials have not confirmed the report.
China is North Korea's only important ally and by treaty returns North Koreans, who Beijing regards as illegal immigrants and not as refugees.
More than 100,000 North Koreans are believed to be hiding in China.
Some information for this report provided by AP and Reuters.