Alec Baldwin has broken his silence after accidentally shooting a cinematographer dead on set.
Crew member Halyna Hutchins, 42, died from her injuries while director Joel Souza fights for his life after a prop gun misfired.
Baldwin responded to the incident on Instagram.
"There are no words to convey my shock and sadness regarding the tragic accident that took the life of Halyna Hutchins, a wife, mother and deeply admired colleague of ours," Baldwin said. "I'm fully cooperating with the police investigation to address how this tragedy occurred and I am in touch with her husband, offering my support to him and his family.
"My heart is broken for her husband, their son, and all who knew and loved Halyna," he said.
An eyewitness recalled that Baldwin said "why was I handed a hot gun?" after he accidentally shot and killed Hutchins.
A witness told Hollywood gossip site Showbiz 411 that Baldwin immediately began asking why he was handed a "hot gun" - which typically means a gun loaded with real ammunition - after the shooting.
A spokesman for the movie's production company later said that accident involved "the misfire of a prop gun loaded with blanks".
However, the prop masters union IATSE 44 told members that it was a live round not a blank.
"A live single round was accidentally fired on set by the principal actor, hitting both the Director of Photography, Local 600 member Halnya Hutchins, and Director Joel Souza," Secretary-Treasurer Anthony Pawluc said in the email, according to IndieWire. "Local 44 has confirmed that the Props, Set Decoration, Special Effects and Construction Departments were staffed by New Mexico crew members."
It comes as photos emerged of Baldwin appearing distraught following the incident. He was seen in tears outside the sheriff's office following the tragic death, according to the Santa Fe New Mexican.
Cinematographer Halyna Hutchins, 42, was killed and director Joel Souza, 48, was injured when a prop gun was "discharged" by Baldwin at the New Mexico production location, the Santa Fe County Sheriff's Office confirmed.
Authorities said Hutchins was taken by helicopter to the University of New Mexico Hospital, where she was pronounced dead. Souza was transported by ambulance to a different facility.
An active investigation is being conducted by the Sheriff's Office but no charges have been filed. Deadline reported Baldwin was questioned and released.
The production company behind the film said in a statement, "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 co-operating with the Santa Fe Police Department's investigation. We will be providing counselling services to everyone connected to the film as we work to process this awful event."
The Sheriff's Office added: "According to investigators it appears that the scene being filmed involved the use of a prop firearm when it was discharged. Detectives are investigating how and what type of projectile was discharged."
Baldwin's brother, actor Stephen Baldwin took to Instagram calling for prayers following the tragedy.
The International Cinematographers Guild paid tribute to their colleague.
"We received the devastating news this evening, that one of our members, Halyna Hutchins, the director of photography on a production called Rust in New Mexico died from injuries sustained on the set," John Lindley, national president of the Local 600 labour union, and Rebecca Rhine, national executive director, said.
"The details are unclear at this moment, but we are working to learn more, and we support a full investigation into this tragic event. This is a terrible loss, and we mourn the passing of a member of our Guild's family."
Director Souza also wrote Rust, which Baldwin is producing as well as starring in. Baldwin had also produced Souza's previous feature, Crown Vic.
Directors Guild of America president Lesli Linka Glatter said in a statement, "The DGA is incredibly saddened to hear of the tragic passing of cinematographer Halyna Hutchins, and the serious injuries sustained by DGA director Joel Souza in an on-set incident in New Mexico today.
"We await further details and a full investigation. Our hearts go out to Halyna's family, to Joel, and to everyone impacted."
Earlier in the day, Baldwin posted a photo of himself dressed in western wear from the set. "Back to in person at the office," Baldwin captioned the post. "Blimey … it's exhausting."
The film was to be centred on outlaw Harland Rust who breaks his teenage grandson out of prison when he is convicted of the death of a local rancher. The duo are then chased by a US Marshal and a bounty hunter.
The movie also starred Titanic's Frances Fisher, Good Boys' Brady Noon, Supernatural's Jensen Ackles and Australian actor Travis Fimmel.
The Rust incident evoked similar on-set tragedies including the 1993 accidental death of actor Brandon Lee on the set of The Crow.
Lee died after he was hit with a bullet which had been lodged in the barrel of a gun, which was fired along with the blank cartridge. Lee was the son of legendary martial arts star Bruce Lee.
In 2017, Gold Coast actor and stuntman Johann Ofner, 28, was shot dead while filming a music video for Australian hip hop group Bliss N Esso. He was killed when a shotgun loaded with blank cartridges was fired at his chest.
In 1984, actor Jon Erik-Hexum died during the production of TV series Cover-Up when he fired a gun loaded with a blank into his temple.
The bullet didn't penetrate his skull but caused a blunt force head injury. He was rushed into surgery but was declared brain dead less than a week later, and his life support was turned off.
The movie Rust is about a 13-year-old boy who is left to fend for himself and his younger brother following the death of their parents in 1880s Kansas, according to the Internet Movie Database website. The teen goes on the run with his long-estranged grandfather after he's sentenced to hang for the accidental killing of a local rancher.
Friends pay tribute to victim
Friends took to Hutchins' Instagram page to leave tributes underneath a video filmed two days ago that showed her riding a horse on her day off.
James Cullen wrote: "I will miss you my friend. This is devastating."
Another friend Jack Caswell added: "I feel like I've had the wind knocked out of me. You will be so missed" while Tina Presley Borek said she is "heartbroken".
Hutchins, who lived in Venice Beach, California, was considered one of Hollywood's rising stars - named in a list of cinematographers to watch in 2019 by American Cinematographer.
The daughter of a soldier, Hutchins grew up on a Soviet military base in the Arctic Circle before going to college in Ukrainian capital Kiev.
She later moved first to the UK to work on documentary filmmaking before traveling to Los Angeles to study for a master's degree in cinematography and switching to movies.
Her credits include horror film Darlin and, shortly before starting work on Rust, she had completed filming on Blindfire - a crime drama starring Brian Geraghty and Sharon Leal.