Nine-year-old girl injured by bison: https://t.co/HEJIPlwICv pic.twitter.com/YXTrBEpQcP

— YellowstoneNPS (@YellowstoneNPS) July 23, 2019

The girl, from Odessa, Florida, was with a group of people in the Old Faithful Geyser area of the park who were standing more than 7 times closer to the bison than park officials recommend. The group eventually caused the bison to charge and toss the child. The injured girl was first treated by emergency medical workers at the Old Faithful Lodge and then taken to the Old Faithful Clinic for further treatment before being released.

A video of the incident, first shared on Twitter Monday, soon went viral. The original video drew more than four million views in the two days before it was deleted, The Washington Post reported.

"My brother and I were looking at the hot springs, and we saw a bunch of people running down the path to the bridge. We saw through the trees some people petting the bison, super close," 18-year-old Hailey Dayton, who filmed the incident, told NBC News. "Because it was agitated by all the people and noise, it just kind of attacked," she added. "After that, everyone was screaming. There were a bunch of kids crying."

The park service said a group of around 50 people had been standing five to 10 feet from the bison for at least 20 minutes before causing it to charge. The park recommends that visitors stand 25 yards from large animals like bison, elk, bighorn sheep, deer, moose and coyotes and at least 100 yards from bears and wolves.

The park said it was still investigating the incident and had not issued any citations.

Bison are responsible for more visitor injuries than any other Yellowstone animal, The Washington Post explained. They are both large and fast: Bulls can grow to be 2,000 pounds and six feet tall, and bison are able to run as fast as 30 miles per hour, three times human speed.

A spate of 33 bison injuries from 1983 to 1985 prompted park officials to launch a safety information campaign, handing out fliers at park entrances and placing warning signs at campgrounds and visitor centers. But some visitors still aren't getting the memo. A 2018 study found that 80 percent of the 25 people injured by Yellowstone bison between 2000 and 2015 "actively approached" the animals. Close to half of them approached in order to take photos, the study found. On average, they were standing around 11 feet from the animals before being injured.

"Every year, there are regrettable accidents caused by people getting too close to these massive animals," NPS said, as The Washington Post reported. "It's great to love the bison, but love them from a distance."