13 firefighters injured battling Rices Fire in Northern California officials say

At least 13 firefighters were injured battling a wildfire burning in Northern California's Nevada County, officials said.

The Rices Fire, which prompted evacuations in Nevada County, has so far burned through at least 904 acres, destroying at least one structure, according to data published by Cal Fire.

At least 373 personnel were involved in fighting the fire, Cal Fire said. As of Thursday, at least 13 had suffered heat-related injuries, local NBC affiliate KCRA-TV reported.

The severity of their injuries is still unclear. Cal Fire did not immediately respond to a request for comment from NBC News.

The blaze was 20 percent contained as of Thursday evening. Residents were told Thursday they could start returning to their homes, KCRA-TV, which is based in Sacramento, California, reported.

Nevada County Sheriff’s Capt. Sam Brown told residents to still exercise caution, however.

“The fire is not out,” he said, according to the Los Angeles Times newspaper. “Our fire partners are assuring us that they’re monitoring and ensuring that things are going the best that they can, but we can’t control Mother Nature.”

He warned that drivers should also make sure to follow posted signs marking areas that are not yet safe to enter.

“We want to get people in their homes, but we also want people to be safe, and we can never guarantee that the fire won’t take a turn,” he said.

The blaze started as a fully involved structure that extended into vegetation, KCRA-TV reported. Fire crews are still investigating the cause of the blaze.