Scott Busby, a senior State Department official for human rights, said Tuesday those coal sales are probably the North's main source of foreign currency. Senior state department official for human rights , Scott Busby , says China using a loophole in UN sanctions to purchase significant amounts of North Korean coal is unacceptable , adding that the coal mines are probably the country 's main source of foreign investment . The US urged China to agree to tighter sanctions in response to nuclear tests carried out on 9 September , and to enforce restrictions that are already in place .
Senior state department official for human rights , Scott Busby , says China using a loophole in UN sanctions to purchase significant amounts of North Korean coal is unacceptable , adding that the coal mines are probably the country 's main source of foreign investment . The US urged China to agree to tighter sanctions in response to nuclear tests carried out on 9 September , and to enforce restrictions that are already in place .