The South Korean humanitarian organization Good Friends said the public execution occurred Feb. 20 in Onseong, North Korea, the Yonhap news agency reported Thursday.

"Most of them had been jailed for trying to cross the river to China to seek economic assistance from their relatives, or for assisting neighbors trying to cross the river," the Buddhist group said in its weekly newsletter without providing sources for the information.

The executions reportedly shocked people in the community since it is not unusual for North Koreans to seek food in China and normally those caught crossing the border are only sent to prison, the North Korea Times reported. It's believed they were intended as a warning to head off the growing number of North Koreans who flee their communist country to escape hunger and political repression.

Aid groups estimate 50,000 to 300,000 North Koreans are hiding in China and face deportation home if found, the news agency said.