San Bernardino shooting: Police officer describes 'unspeakable carnage' at scene

'Surreal' scenes of victims moaning and fire alarms blaring in a room full of Christmas decorations greeted officers

First responders gather on a nearby street corner as victims are treated outside a social services center in San Bernardino (AP)

One of the first police officers to arrive at the mass shooting in southern California in which 16 people were gunned down at an office Christmas party has described the “unspeakable carnage” at the scene.

Officer Mike Madden said he saw “pure panic” on the faces of the injured as they made their way into the social services centre where the attack took place.

Lt Madden described “surreal” scenes of victims moaning, the smell of gunpowder, blood and fire alarms blaring in a room adorned with Christmas decorations.

He said it was immediately evident reports of multiple dead and injured were “100 per cent true”.

Syed Rizwan Farook, 28, and Tashfeen Malik, 27, killed 14 people and wounded 21 when they stormed a Christmas party armed with semi-automatic rifles and handguns at the Inland Regional Centre in San Bernardino on Thursday.

The couple were later shot and killed by officers after fleeing the scene.

Lt Mike Madden describes the "surreal" scenes at San Bernardino shooting YouTube (YouTube)

“It was unspeakable, the carnage that we were seeing,” Lt Madden told a news conference, reported by KTLA5. “The number of people who were injured and unfortunately already dead.

“The pure panic on the face of those individuals that were still in need and needing to be safe.”

Lt Madden said the first officers to enter the building made the difficult decision not to attend immediately to the injured.

“That was a difficult choice to have to make as well, passing people that we knew were injured and in need of assistance.

“But our goal at that time had to be trying to locate the shooters and deal with them.”

Lt Madden said: “It’s something you’re never actually prepared for.

“This is a tragedy I have never experienced in my career. But everyone who responded knew we had to bring calm to the chaos that was going on.”

Farook, who was an employee of San Bernardino County and attended the Christmas party at the Inland Regional Center, stormed out and later returned to fire on the celebration, said Jarrod Burguan, police chief in the city of San Bernardino.

Scene at the San Bernardino shooting AP (AP)

The couple are believed to be the only shooters, and while the motive remained unclear, Mr Burguan has not ruled out terrorism.

In a house in the nearby town of Redlands associated with the couple, police found more than 2,500 round of .223 ammunition, 2,000 bullets for the hand guns and 12 pipe bombs.

They also found tools, which could have been used for the production of more bombs.

On Thursday, President Barack Obama stressed that the FBI was still investigating the incident and had not yet come to a conclusion as to the motive that lay behind the shooting he also repeated his case for new gun control measures.