Foreign TV and radio broadcasts are more effective than sending balloons when it comes to sharing information with North Korean people, U.S. Special Envoy for North Korean Human Rights Issues Robert King said at a Washington, D.C. conference on Tuesday.

"When you look at the overall impact of the balloons that may or may not reach North Korea, (they're) far less effective (compared to) the people listening by radio and watching South Korean television," King said.