The former soldier who killed three workers at a veterans' home in California on Friday before turning the gun on himself had been asked to leave its PTSD program days before the rampage, it has been revealed.

Albert Wong, 36, killed Christine Loeber, Jen Golick and Jennifer Gonzalez on Friday at the Veterans Home of California in Yontville, Napa, after a lengthy standoff where he took them hostage.

He stormed the building at 6pm as the women, who all treated patients, celebrated a co-worker's leaving party with ice cream and cake.

On Friday, North Bay Senator Bill Dodd confirmed that Wong, who served in Afghanistan in the US Army, had recently been treated at the home but was asked to leave earlier this week.

It is not known what prompted doctors to kick him off the PTSD program but Bob Golick, Jen Golick's father-in-law, said it was her who expelled him.

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Albert Wong, 36, had been receiving treatment at The Pathway Home in California before being asked to leave its PTSD program. On Friday, he killed executive director Christine Loeber, 48, (circled right) and two doctors then turned the gun on himself

On Saturday morning, President Trump offered his condolences to the families of the three women who were murdered.

'We are deeply saddened by the tragic situation in Yountville and mourn the loss of three incredible women who cared for our Veterans,' he said.

Department of Defense officials say Wong served on active duty from May 2010 to August 2013.

Wong was awarded four medals. He spent a year in Afghanistan for which he was awarded the Afghanistan campaign medal with two campaign stars.

He was also awarded Expert Marksmanship Badge with Rifle.

Albert Wong, 36, (pictured) has been identified as the suspect who stormed the largest veterans home in the US and shooting dead three woman before killing himself on Friday

President Trump acknowledged the tragedy on Twitter on Saturday morning

Loeber, 48, was the executive director of the Veterans Home and Golick, 42, and Gonzalez, 29, were both doctors.

The home is a Pathway Home which is a privately run program.

For nearly ten hours on Friday, officials tried to negotiate with Wong as he held the women hostage inside.

Others who were there when he arrived with his rifle were able to escape.

Executive Director Christine Loeber, 48, (left), Dr Jennifer Gonzales, 29, (right) were two of the three women killed at the Veterans Home of California, Yontville in Napa on Friday

Dr Jen Golick, a 42-year-old therapist at the veterans home, was also killed during the shooting

Wong died by suicide at the home after a 10 hour standoff

The Pathway Home released a statement on Friday night hailing the three victims for their dedication.

'These brave women were accomplished professionals who dedicated their careers to serving our nation's veterans and working closely with those in the greatest need of attention after deployments in Iraq and Afghanistan,' the statement read.

'All of us at The Pathway Home are devastated by today's events. We stand with the families, friends, and colleagues who share in this terrible loss.'

Gunfire was first reported at 10.20 am after the suspect stormed a going away party being held at the home on Friday.

It is a tragic ending to a day-long standoff with police that saw more than 30 shots fired at officials. Above, officials at the scene during the standoff

Gunfire was first reported at 10.20 am after the 36-year-old man stormed a going away party being held at the Yontville Veterans Home in Napa, California

A SWAT team is pictured at the scene on Friday. They engaged in a 10-hour long standoff with Wong which ended when he shot himself

Authorities said the gunman was armed and wearing a bulletproof vest when he slipped into the facility, which is the largest veterans home in the US.

Napa County Sheriff's spokesman Christopher Childs said the suspect initially had more hostages but released some of them earlier in the day.

Three law enforcement agencies had hostage negotiating teams at the scene, but Childs said they were unable to make any contact with the shooter.

Fernando Juarez, 36, of Napa, center, embraces his 22-year-old sister Vanessa Flores, a caregiver at the facility who exchanged texts with family while sheltering in place

Napa County Sheriff's spokesman Christopher Childs (pictured) said the suspect initially had more hostages but released some of them

Officers entered the room where the hostages were being held around 6pm and found that all four were dead.

A motive has not yet been determined and it remains unknown if the women were chosen at random, according to Childs.

'This is a tragic piece of news, one that we were really hoping we wouldn't have to come before the public to give,' he said during a press conference.

The suspect's rented vehicle was found at the veterans home's parking lot, and a cellphone was located inside.

'There is no threat to public safety at this time,' Childs added.

California Gov Jerry Brown released a statement late Friday night offering his condolences.

'Anne and I are deeply saddened by the horrible violence at the Yountville Veterans Home, which tragically took the lives of three people dedicated to serving our veterans,' he wrote.

'Our hearts go out to their families and loved ones and the entire community of Yountville.'

Law enforcement vehicles are seen from this helicopter shot above the veterans' home in Yountville

This is the home which Wong stormed and where he was being treated until earlier this week

Within four minutes of the 911 call on Friday morning, authorities said the gunman and a Napa County Sheriff's deputy exchanged gunfire.

Officers confirmed that he had fired up to 30 shots towards police but said there were no injuries.

The 600-acre facility, which is home to 840 veterans, was placed in lockdown from 10.40am local time on the West Coast.

As law enforcement officers surrounded the building, residents and workers at the facility reported that they were sheltering in place.

Jim Thomas, vice president of the Veterans' Group at the Yountville Veterans Home, said the facility should have been protected with a gate guard.

The Veterans Home is pictured from a distance. It is the largest in the United States

'Anybody can walk into this property with an AR-15 or some other weapons and go to our dining hall, kill 300 people in one meal,' he told The Mercury News.

'We've complained for years here, and the people at CalVet in Sacramento don't seem to be willing to do any of that.'

Larry Kamer said his wife, Devereaux Smith, was 'face-to-face' with Wong.

'All I know is she said it was all very calm,' he recalled. 'He walked in with a rifle so people had a clear understanding what was going on.'

Smith told Kamer that she was allowed to leave the room with three others and heard gunshots when she left.

Eddie Thornton took to Twitter and reported that his father and friends were 'barricaded in rooms.'

Another employee wrote on her Facebook page: 'Please pray we have about 30 police here at the Vets Home there is a shooter here. We're in lockdown in the MSC Building.'

Yvette Bennett, a wound-care supply worker who supplies the veterans center, was turned back when she tried to deliver what she said were urgently needed medical supplies for two patients inside.

Of all the medical institutions she has worked with, 'this is the most placid, calm, serene place,' she said. Earlier this week, when she last visited, Bennett asked a doctor, 'What's your magic here?'

'And then 48 hours later this happens,' she said.

Golfers from a nearby vineyard that borders the property were evacuated from the area as a precaution.