A visitor was injured in a bison attack Wednesday at Yellowstone National Park, which this week began a phased reopening.
"A female visitor was knocked to the ground and injured by a bison," the National Park Service said in a statement.
The injury happened Wednesday afternoon in the Old Faithful Upper Geyser Basin when the woman got too close to the animal, park officials said.
The extent of her injuries was not known. "She was assessed and refused transport to a medical facility," the park service said.
Officials said it was the first bison attack on a visitor this year at America's first national park, which exists mostly in Wyoming.
The park reopened Monday at the behest of President Donald Trump after closing March 24 to encourage people to stay at home during the coronavirus pandemic.
On May 13, Trump said, "The parks are opening — and rapidly, actually."
Yellowstone's phased reopening includes access to two of the park's five entrances and allows visitors to tour sightsee in the lower loop of the park.
"When an animal is near a trail, boardwalk, parking lot, or in a developed area, give it space," the park service said. "Stay 25 yards (23 m) away from all large animals - bison, elk, bighorn sheep, deer, moose, and coyotes and at least 100 yards (91 m) away from bears and wolves."
The attack was under investigation.