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.
One person is dead and at least four are injured in the desert oasis of Palm Springs, Calif., after a bomb exploded on Saturday morning outside a fertility clinic, damaging buildings and leaving windows shattered across several blocks in what authorities called a terrorist attack.
“This explosion was significant,” said Akil Davis, the assistant director in charge of the F.B.I.’s Los Angeles Field Office. “Make no mistake, this is an intentional act of terrorism.” He added that officials believed the clinic was specifically targeted.
Mr. Davis said that the bureau had begun one of the largest bombing investigations ever in Southern California and that it was not yet clear whether the event had been an act of domestic or international terrorism. Authorities have identified a person of interest but did not name the person on Saturday afternoon. They also did not say whether the person who died was connected to the blast. Mr. Davis said that “we are not actively out searching for a suspect.”
The explosion was in or near a vehicle parked by the clinic, according to the mayor, Ron deHarte. But many other details were unclear, including the vehicle’s make and model. All that was left of it at the scene was an axle, authorities said.
The bombing was an isolated incident and the community was no longer at risk, Andy Mills, the Palm Springs police chief said.
Reports of a loud boom and images of broken glass and billowing smoke began to be shared on social media around 11 a.m. local time. The blast area extended for blocks, and some buildings were severely damaged, with shattered windows visible in many restaurants, shops and apartment buildings throughout the city’s downtown.
A phone number for the clinic, American Reproductive Centers, did not appear to be in service on Saturday.
A website for the office listed fertility treatments, such as in vitro fertilization and egg freezing, among its services and describes its work helping L.G.B.T.Q. couples have children. In a Facebook post, the clinic reported that none of its staff were harmed in the explosion and that the eggs, embryos and other materials in its lab were “fully secure and undamaged.”
“We are heavily conducting a complete safety inspection and have confirmed that our operations and sensitive medical areas were not impacted by the blast,” the clinic wrote on its Facebook page, adding that it expected to be open for normal operations on Monday.
“I really have no clue what happened,” Dr. Maher Abdallah, who runs the clinic, told The Associated Press. “Thank God today happened to be a day that we have no patients.”
Planned Parenthood clinics in the area reported no threats of danger but closed 19 health centers across Southern California on Saturday out of an abundance of caution, a spokesperson said.
Palm Springs, about 100 miles east of Los Angeles, is known for its stunning mid-century modern architecture, arid desert landscapes and thriving L.G.B.T.Q. community. In 2017, it became the first city in the country with an entirely L.G.B.T.Q. city council. Politically, Palm Springs is a liberal city in an otherwise more conservative region of California.

The area where the blast occurred is on the edge of neighborhoods made famous for vacation homes of Hollywood stars from the past. It sits about a mile and a half from a large sculpture of Marilyn Monroe, who was known to escape to the desert town.
The bombing occurred as in vitro fertilization has become increasingly politicized in the debate over reproductive rights, while dividing social conservatives.
Many Christian conservatives who oppose abortion also oppose I.V.F. because they do not support the loss of embryos, which they consider people. Embryos are routinely discarded during I.V.F. if they fail to develop.
Prominent Republicans have repeatedly disavowed efforts to limit I.V.F. President Trump, who has declared himself the “fertilization president,” has promised to expand access to the procedure.
Still, some right-wing Christian activists have moved ahead with efforts to restrict the procedure. Last year, the Southern Baptist Convention, the country’s largest Protestant denomination, opposed the use of I.V.F. for the first time, even though the procedure is popular among evangelical families. And last year, several state Republican parties added anti-abortion language to their platforms, indicating an openness to restrictions on I.V.F.
On Saturday, videos showed flames licking the shattered terra-cotta tiles of the clinic’s roof as debris clogged its entrance.
Claudio Chavez, who works at an upholstery shop near the explosion, said his store’s windows had been blown out.
“I was just in my shop waiting for clients, and all of a sudden it felt like a big explosion,” he said. “It took out our window. I just saw a bunch of smoke.”
He said people came out of homes and businesses onto the street to see what happened. Mr. Chavez, a logistics manager at the shop, said he began picking up debris and sweeping up broken glass.
Matt Spencer helped evacuate his nearby apartment complex and then noticed debris in the street that resembled remnants of a car. He said that he knew it was a car because he could see the tire rims through the flames. Pieces of the car, he said, were “blown clear across four lanes.”
Other parts of the car became embedded in the side of a building, he added, and all the windows in a hotel were blown out.
Scott Pastorius, 61, a construction project manager from Los Angeles, was sitting in his vacation home four blocks away from the explosion site when he heard a loud boom.
“My initial response was earthquake, but in a split second I realized it was too intense,” he said. “The whole house rattled and then the glass in the door I saw flexing.”
Mr. Pastorius said he ran into his backyard, where he saw a plume of smoke billowing nearby. He grabbed his camera, got in his car and drove to the scene.
The Desert Regional Medical Center across the street, as well as a liquor store and a pancake house, had windows blown out, he said. A nearby hotel also had doors blown off and its portico was damaged, Mr. Pastorius said.
Mr. Pastorius said the roof of the fertility clinic had collapsed and that the entire back side of the building had been blown out. Debris from the explosion shot across the street to the other curb, he said.
“That was a very intense explosion,” he said.