The group in Roosevelt, a town of 8,000, had traveled about 125 miles east from the Salt Lake City area to watch a relative play his final game for Union, which lost to rival Uintah and finished the season without a victory.
The group reportedly was trying to boost Union's morale with the Haka as the players left the field.
Spectators, coaches and players told police that everything was fine and they should let the men perform, Jessica Rasmussen said, but officers asked them to make room and started using pepper spray.
Rasmussen said she and other bystanders also got spray in their eyes, ears and mouths.
Union fan Jason Kelly said the way police reacted was an embarrassment to the community of Roosevelt.
"I've never seen anything like it," Kelly said. "It was totally unprovoked."
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