The act was being investigated as a possible car explosion, said two law enforcement officials briefed on the matter who insisted on anonymity to discuss preliminary information from an ongoing investigation.

At least one person was believed dead, said one of the officials. Authorities have not disclosed a motive.

The city of Palm Springs said Saturday in a social medial post that the explosion happened at 11 a.m. local time and that residents were being asked to avoid the area around North Indian Canyon Drive near East Tachevah Drive.

Investigators from the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives were on their way to the scene to help assess what happened.

Dr. Maher Abdallah, who runs the American Reproductive Centers fertility clinic, confirmed that his clinic was damaged. He told The Associated Press in a phone interview that all of his staff were safe and accounted for.

The explosion damaged the practice’s office space, where it conducts consultations with patients, but left the IVF lab and all of the stored embryos there unharmed.

“I really have no clue what happened,” Abdallah said. “Thank God today happened to be a day that we have no patients.”

Aerial footage showed a burned-out car in a parking lot behind the building that housed the fertility clinic’s office space. The blast caved in the building’s roof and blew a wide debris field across a sidewalk and four lanes of the street on the other side of the structure.

Rhino Williams, 47, was chatting with customers at a restaurant he helps manage inside the Skylark Hotel just over a block away from the scene when he heard a huge boom. Everything rattled, he said, and Williams — who has a background in aviation — immediately sprinted to the scene to see if anyone was in need of help, thinking a helicopter might have crashed.

Williams saw a large dark grey plume of smoke and covered his nose with his shirt as he smelled burning plastic and rubber. He said he saw a building had “blown out” into the street, with bricks scattered everywhere, and spotted a car’s axle on fire in the building’s parking lot.

He said it was the only car in the lot that he saw. He ran into the building, calling out and peering behind the counter to see if anyone was inside. He did not hear a response and did not see anyone behind the counter.

Williams said he ran around to check on other nearby buildings. Multiple windows of the neighboring liquor store were also blown out, he said. Once he saw authorities arrive, he headed back to the hotel.

Nima Tabrizi, 37, of Santa Monica, said he was inside a cannabis dispensary nearby when he felt a massive explosion.

“The building just shook, and we go outside and there’s massive cloud smoke,” Tabrizi said. “Crazy explosion. It felt like a bomb went off. … We went up to the scene, and we saw human remains.”

Palm Springs is a tony community in the desert about a two-hour drive east of Los Angeles. Its known for upscale resorts and a history of celebrity residents.