Thursday 15th November 2012, 10:28 AM:

A South Korean Air Force T-50 training jet has crashed into mountains in the NE of South Korea. Cause of the crash is unclear, and it is not known if the pilot ejected safely.

Link - Yonhap News Agency:
http://ow.ly/fiSQX

Background:
The T-50 is a single-engine training jet, and also is ROK's first indigenous jet, becoming operational in 2010. It has supersonic performance, which is unusual in a training aircraft.
Rok_t50_image_16nov12

(Image - Korea Times)