Three Chinese fishermen were killed after a clash with South Korean coastguard on Thursday just about 70 kilometers off South Korea's southwestern coast.

An official from the coastguard said the fishermen might have died of smoke inhalation caused by the fire. The fire itself was a result of a flashbang or stun grenade being thrown by the officers as they were entering the Chinese fishing vessel.

The incident happened when the coastguard confronted the fishing boat within South Korean waters. The officers had first ordered the fishing boat to stop in order to be inspected.

However, according to officials, the men ignored the commands and continued to move forward. As the coastguard vessel stopped the fishing boat and the officers began to board, the men barricaded themselves inside the wheel house.

The officers then fired a flashbang or stun grenade into the locked steering room, after which a fire broke out quickly engulfing the rest of the boat.

Fourteen other fishermen survived the encounter and were taken to a South Korean port for questioning by the authorities.

A full investigation was requested by the Chinese authorities in which the South Korean coastguard reported is already being conducted.

Flashbang or stun grenades are considered to be non-lethal, producing an ear splitting noise and an intense flash of light which temporarily affects the vision. It can also disrupt the balance of a person by impacting the fluids in the inner ear.

With proper authorization, Chinese vessels have permission to fish within the confines of the South Korean waters, but illegal fishing has become rampant due to the fishermen venturing far from the barren waters within the borders of China and this has recently put a strain on the two countries.