A nine-year-old girl was charged and injured by a bull bison at Yellowstone National Park on Monday. She was treated by medical staff in the US park before being released, officials say.

Witnesses say the bison was surrounded by a group of 50 visitors, far closer than the recommended distance away, for about 20 minutes before it charged.

In a statement, Yellowstone Park officials blamed the proximity of the group for the bison charging. They also reiterated official advice to stay 70ft (23m) from all large animals in the park - including bison, deer and moose.

The park, which is mostly in the state of Wyoming, also tells visitors to keep at least 300ft away from any bears and wolves they see.Official advice says wild animals in the park should never be fed or approached by visitors.

"Wildlife in Yellowstone National Park are wild," they said in a statement. "When an animal is near a trail, boardwalk, parking lot, or in a developed area, give it space. If need be, turn around and go the other way to avoid interacting with a wild animal in close proximity," the statement added.

The statement says no citations have yet been issued to the family, but the incident is still under investigation.

Yellowstone is home to the largest collection of bison on public land in the US. The animals are the largest land-dwelling mammals in North America, and can weigh up to 2,000lb (900kg).

Yellowstone officials say bison can run up to 30mph (50km/h) and are the animal responsible for the most amount of injuries within the park.

A series of injuries at Yellowstone National Park has officials warning tourists that selfies and bison don't mix.

A 43-year-old Mississippi woman was thrown into the air recently after she turned her back on a bison to take a photo of herself with it.

Four other tourists have been hurt in similar incidents this year, Yellowstone officials said. Previously bison attacks had been unusual, they added.

"The (woman) said they knew they were doing something wrong but thought it was OK because other people were nearby," park spokeswoman Amy Bartlett told the Associated Press. "People are getting way too close."

The woman and her daughter got within about 18ft (5.5m) of the animal near the Fairy Falls trailhead just outside Old Faithful. The sprawling park is mostly located in north-west Wyoming. Someone warned them that they were too close, but the bison charged and the woman could not run away fast enough.

If you are walking with a dog and cows chase you let the dog go .
They will always chase the dog and as dogs are faster they will save themselves .
Laws are quite nervous and usually are easy to frighten off .
Make sure there are no bulls before you flap a coat at them !