The South Korean military on Monday shot and killed a man who was trying to swim across a river to North Korea, a military spokesman said.

The man jumped into the Imjin River at the heavily fortified border between the two Koreas and refused to stop when South Korean military service members shouted at him to come back, said Kwon Ki-hyun, a South Korean military spokesman.

Following the rules at the border zone, the military then shot him and he died, Kwon said.

Military officials are trying to identifying the man, Kwon said.

While tens of thousands of people have managed to flee to South Korea from the authoritarian regime in the North, defections in the other direction are very rare.