A single live round struck both the cinematographer and the director on the 'Rust' set, according to union

• A single live round that was fired from a prop gun by Alec Baldwin reportedly hit both a cinematographer and a director.
• The details about the Thursday incident in New Mexico were revealed Friday by a prop masters union.

A single live round that was discharged from a prop gun by actor Alec Baldwin on the set of his latest movie struck both the cinematographer - who was killed - and the director of the film, according to a prop masters union.

The International Alliance of Theatrical Stage Employees Local 44 revealed the details about the Thursday afternoon fatal incident in New Mexico in an email to its members Friday.

"A live single round was accidentally fired on set by the principal actor, hitting both the Director of Photography, Local 600 member Halyna Hutchins, and Director Joel Souza," IATSE Local 44 union secretary-treasurer Anthony Pawluc told members in the email, seen by IndieWire.

Authorities say Baldwin fatally shot 42-year-old Halyna Hutchins, the director of photography, and injured director Joel Souza, 48, when he discharged the prop gun on the set of "Rust," a Western flick he was making in Santa Fe.

A source in the union told the Los Angeles Times that it remains unclear what type of projectile was in the gun, and that "live round" in the film industry refers to anything loaded into a gun, including blanks.

Pawluc described the incident in the email as "an accidental weapons discharge."

"Local 44 has confirmed that the Props, Set Decoration, Special Effects, and Construction Departments were staffed by New Mexico crew members. There were no Local 44 members on the call sheet," the email read.

Santa Fe County Sheriff's deputies were dispatched to the Bonanza Creek Ranch movie set Thursday after a shooting was reported, officials said.

Hutchins was rushed via helicopter to the University of New Mexico Hospital where she was pronounced dead, according to authorities.

Souza was hospitalized for his injuries and later released.

Baldwin broke his silence about the on-set shooting in a tweet Friday, saying his "heart is broken."