Alec Baldwin discharged a prop firearm on the set of a Western he was making in New Mexico on Thursday, killing the film’s director of photography and wounding the movie’s director, the authorities said.

The cinematographer, Halyna Hutchins, 42, was killed, and the director, Joel Souza, 48, was injured around 1:50 p.m. on the set of “Rust,” which is being filmed in Santa Fe County, said Juan Rios, a spokesman for the Santa Fe County Sheriff’s Office. The circumstances of the shooting are under investigation.

Mr. Rios said the shooting at Bonanza Creek Ranch happened in the middle of a scene that was either being rehearsed or filmed. He said the Sheriff’s Office was interviewing people on the set to determine how the two had been shot.

“We’re trying to determine right now how and what type of projectile was used in the firearm,” he said.

Mr. Rios said on Thursday night that the Sheriff’s Office had not filed charges against anyone in connection with the shooting.

Ms. Hutchins was flown to the University of New Mexico Hospital in Albuquerque, where she later died, Mr. Rios said. Mr. Souza was taken to Christus St. Vincent Regional Medical Center in Santa Fe. Mr. Souza’s condition was not immediately available.

The film’s producers and a representative for Mr. Baldwin, 63, did not immediately respond to emails or phone calls on Thursday night.

In a statement, the movie’s production company, Rust Movie Productions LLC, said: “The entire cast and crew has been absolutely devastated by today’s tragedy, and we send our deepest condolences to Halyna’s family and loved ones. We have halted production on the film for an undetermined period of time and are fully cooperating with the Santa Fe Police Department’s investigation. We will be providing counseling services to everyone connected to the film as we work to process this awful event.”