The explosion on Saturday morning, which occurred in or near a vehicle less than a mile from downtown Palm Springs, Calif., was “an intentional act of terrorism,” the F.B.I. said.

Authorities are investigating after an explosion severely damaged American Reproductive Centers, a fertility clinic that offers IVF treatments in the Coachella Valley, along with other nearby buildings.

Rhino Williams was chatting with customers Saturday at a hotel restaurant he helps manage when he heard the explosion that tore through a fertility clinic in the California city of Palm Springs late Saturday morning.