Fijian authorities are trying to verify this sickening video of the brutal killing of fisherman at sea, much of it too graphic to be shown.

WARNING: GRAPHIC VISION of fisherman shot dead in the water

A SHOCKING YouTube video showing what appears to be Fijian fishermen being shot and killed at sea is being investigated by the South Pacific nation’s police.

The video, which has not been verified, shows four men clinging to an upturned boat and debris.

They appear to have been shot from close range and left floating in the sea.

Onlookers on board one of the attacking boats, which could be a tuna fishing vessel, do nothing to stop it.

They are heard laughing and are shown smiling at the camera at the end of the horrific 10-minute amateur video.

Fiji police are reportedly appealing to Interpol for help to verify details of the video.

Fiji assistant police commissioner Rusiate Tudravu told the ABC’s Radio Australia network it was too early to make a statement.

“We have not received any formal complaints and I have not yet seen the video,” he said.

It’s still to be verified whether or not the men being shot are Fijian.

While the video was posted on YouTube on Monday, it’s also not clear when it was recorded.

User “commonkingssavou” describes the footage as “Fishing vessel fijian crew gettin shot, out side fiji waters (sic)”.

It’s already been viewed more 20,000 times, despite YouTube imposing age-restricted access.

In one shot, the insignia of one of the attacking boats can be seen.

Distorted images of flags on the vessels appear to be from Asian countries.

A YouTube spokesman said the company didn’t comment on individual videos.

The service’s guidelines generally prohibit graphic or violent content, but YouTube does make exceptions for material “with clear documentary or news value”, the spokesman said.

“In cases where a video is not suitable for all viewers, we take care to apply appropriate warnings and age-restrictions to safeguard people using our site.”