A whale has died after being harpooned and shot with a machine-gun by aboriginal hunters near Vancouver Island, a U.S. Coast Guard official said Sunday.

Petty Officer Kelly Parker said five people, believed to be members of the Makah band based in Neah Bay in Washington State, killed the California grey whale on Saturday.

Parker said the hunt took place in the Strait of Juan de Fuca, near Washington's western tip.

"The five individuals involved were picked up by police but no charges have been laid," said Parker.

The Makah band has treaty rights to kill whales for traditional, sustenance purposes.

However, the U.S. National Marine Fisheries Service (NMFS) said the use of a machine-gun may not qualify.

Officials from the service are trying to determine whether, as some reports have indicated, the whale was harpooned and shot in a humane attempt to kill it after it had become entangled in a fishing net and couldn't get loose.

The Makah conducted a whale hunt for the first time in 70 years in 1999, with the permission of the U.S. government and the Makah Tribal Council.

The resumption of the traditional whale hunt spurred great controversy. Environmental groups won a court ruling in 2002 that ordered the Makah not to carry out the hunt again until the band got a waiver under the Marine Mammal Protection Act, which bans whale hunts in the United States.

Since then the Makah Tribal Council has been trying to get the waiver and permission to kill up to five whales a year.

Under the Marine Mammal Protection Act, the men who killed the whale could face fines of up to $20,000 US each, NMFS spokesman Brian Gorman told the Seattle Times.

With files from the Associated Press