(AP) — Part of Yosemite National Park has been closed as a wildfire quintupled in size near a grove of California’s famous giant sequoia trees, officials said.

The fire forced park officials on Thursday to close Mariposa Grove, which has the largest sequoia grove in Yosemite and features more than 500 mature giant sequoias. The rest of the national park is open.

The blaze grew from 46 acres (19 hectares) Thursday night to 250 acres (101 hectares) by Friday morning with no containment, said Nancy Phillipe, a Yosemite fire information spokesperson.

The sequoias are threatened by the flames, but there have been no reports of severe damage to the grove’s named sequoias, such as the 3,000-year-old Grizzly Giant, Phillipe said.

Some park visitors had to be evacuated from the fire zone Thursday, but there were no injuries. Access to the grove was closed to allow firefighters easier access to the flames, Phillipe said.

“Our priorities are certainly the giant sequoias and the community of Wawona,” which lies within the park, she said.

The fire was first reported on the park’s the Washburn Trail — for which the fire was then named — in the Mariposa Grove’s lower section on Thursday around 2 p.m. by 911 callers, Phillipe said. It’s cause remains under investigation.

Crews are fighting the blaze by ground and air in hopes of preventing the fire from spreading.

“We’re really hitting it hard, as much as we can,” Phillipe said.