South Korea and the Democratic People's Republic of Korea have engaged in a naval exchange of fire along their disputed western sea border, with a DPRK vessel reportedly suffering heavy damage before withdrawing back across the demarcation line.

South Korean military officials said there were no South Korean casualties, and it was not immediately clear if there were any casualties on the DPRK side.

A DPRK patrol boat allegedly crossed the disputed western sea border on Tuesday morning, drawing warning shots from a South Korean Navy vessel. The DPRK ship then opened fire and the South Korean frigate returned fire before the DPRK vessel sailed back to home waters.

Preliminary reports suggest the DPRK ship was seriously damaged in the skirmish, while the South Korean ship was unscathed. There was no immediate comment from the DPRK on the clash.