Reports of a mass shooting in California, 28 casualties confirmed.

Fourteen people are confirmed dead and at least another 14 are injured in a mass shooting in the Californian city of San Bernardino.

The shooting reportedly occurred late Wednesday morning at the Inland Regional Centre, which has been described as a developmental disability centre for young people.

SBFD units responding to reports of 20 victim shooting incident in 1300 block of S. Waterman. SBPD is working to clear the scene.

— San Bernardino Fire (@SBCityFire) December 2, 2015

Two of the suspects have reportedly been killed in a shoot out with police on a residential street. A third is still at large.

Local county police chief Jarrod Burguan confirmed that 14 people had died.

“Upwards of 14 people are dead and upwards of 14 people are wounded. Keep in mind these are preliminary numbers,” he said.

Burguan  said the shooters were “on a mission”.

“What we have so far is up to three people have entered the building and have opened fire on people in the building,” he said.

“These are people that came prepared they were dressed in a way to indicate that they were prepared and they had long guns.”

Both the FBI and the Federal Alcohol Tobacco and Firearms (AFT) agency are working with the local police.

Terry Petit’s daughter works at the center. He got a text message from her that said she was hiding after hearing gunshots.

Petit choked back tears as he read the texts for reporters outside the center. He said she wrote: “People shot. In the office waiting for cops. Pray for us. I am locked in an office,” the Associated Press reports.

Some US Presidential candidates have tweeted responses to the crisis.

Another woman, who’s brother is a social worker at the center, told ABC 7 News that she didn’t understand why the shooting had happened.

“It doesn’t make sense, why people would shoot people who help others?”

She said her brother had sent her a series of texts about the situation.

“Him and his coworkers had to lock themselves in an office and he saw people who got shot,” she said.

“He just saw the people wounded and so him and other co-workers tried to get somewhere safe.”

Chief Burguan said police had active leads, but would not discuss them.

But he said there was no indication that the shooting was linked to any terrorist groups at this stage.

“We have no information at this point to indicate that this is terrorist related in the traditional sense that people might be thinking,” he said.

“Obviously at a minimum this is domestic terrorism.”

A recording of the first 15 minutes of the police response to the shooting that has been uploaded to Soundcloud records the first description of a shooter.

“So far I am getting on the ground floor unknown race male all black clothing with a black mask. We do have victims down,” the dispatcher says.

“Now we have two suspects both dressed in black. On the inside of the business,” one officer says.

In an update for local media Sergeant Vicki Cervantes said that police are currently trying to remove all witnesses and victims from the building.

“We don’t have numbers yet on casualties but there are multiple casualties and there are fatalities,” she said.

Sgt Cervantes said the centre was hosting an event, which was possibly the target of the shooting.

“They had some type of function there today, an event, and during that event is when multiple shooters came in and just started shooting.

“We were told that at least one of the shooters may have left in a black SUV from the location,” she said.

More to come.