One person is in custody as authorities investigate the “isolated incident.”

The San Francisco Police Department discovered chemicals to make explosives near an RV park Friday night.

“On Jan. 15 2021 at approximately 5:11pm, we responded to the 600 block of Gilman Ave to assist Federal Agents with an investigation. FBI agents on scene located chemicals used to make explosives,” the police department announced on Twitter.

“The resident of an RV was detained and nearby residents were evacuated,” they added.

In Google Maps, the address provided by the police is listed as being on the same block as Candlestick RV Park.

“The SFFD and our EOD Unit responded to the scene,” police said. “This appears to be an isolated incident and the investigation has been turned over to the department. Residents that were evacuated are receiving necessary assistance with temporary shelter.”

They said the investigation is ongoing and is in its early stages. No more information is currently available.

The news comes as law enforcement officers across the country are on high alert following the U.S. Capitol attack on Jan. 6 and ahead of President-elect Joe Biden’s inauguration on Jan. 20.

The RV park did not answer the phone when ABC News reached out for comment.