WOUNDED KNEE, S.D. (AP) — A wildfire has burned about 750 acres (304 hectares) of the Pine Ridge Indian Reservation in South Dakota, but crews have encircled much of the fire and it no longer is growing, officials said Tuesday.

The fire was reported Friday evening on the west side of the reservation, located in southwest South Dakota, as it tore through trees and heavy vegetation.

Jon Siedschlaw, deputy director of Oglala Sioux Tribe Emergency Management, said the fire was still burning inside a line dug with heavy equipment. No homes or other structures have burned, he said.

The cause of the fire is under investigation.

The Bureau of Indian Affairs’ Pine Ridge Agency, which is leading the firefighting effort, didn't respond to inquiries from The Associated Press about the blaze, but in a Facebook post the agency said Monday evening that the fire was 80% contained.

“Fire is holding inside the heavy equipment line. Even with the rain some areas inside the perimeter have started to smoke again. Smoke will be visible for the following weeks,” the post said. The agency said in other social media posts that crews will continue responding to the fire this week.

The fire was spotted Friday between Manderson and Wounded Knee. It spread with the help of wind gusts of 45 mph (72 kph), the agency said in a post.

Pine Ridge is the largest Native American reservation in South Dakota and one of the largest in the U.S. It comprises about 2.1 million acres (850,000 hectares), according to the Pine Ridge Agency’s website.