Hilaria Baldwin speaks out about fatal shooting on 'Rust' set

Hilaria Baldwin has broken her silence over the deadly accidental shooting that occurred last Thursday, when her husband, actor Alec Baldwin, allegedly fired a pistol, fatally striking cinematographer Halyna Hutchins and injuring the film's director.

"My heart is with Halyna. Her husband. Her son. Their family and loved ones. And my Alec," Baldwin posted. "It's said 'There are no words' because it's impossible to express the shock and heartache of such a tragic incident."

"Heartbreak. Loss. Support," she concluded.

An assistant director handed the prop gun -- one of three on hand -- to Baldwin, and said, "Cold gun," to let the crew know that a gun with no live rounds was being handled, according to a search warrant from Santa Fe County obtained by ABC News. Baldwin then fired, hitting Hutchins and Souza. The assistant director told investigators that he didn't know there were rounds in the gun he gave to the actor, according to the warrant.

Police are still investigating the incident on the set of "Rust."

There were safety concerns raised by crew members on the film's New Mexico set, ABC News learned. Gun safety concerns had been "brushed off" by its producers, a camera crew member told ABC News after the incident.

Producers, including Baldwin, are cooperating with local authorities' investigation.