In 2015 alone, there have been 352 mass shootings in the US

In 337 days of 2015, mass shooting in the US rose to 352 on Thursday, following an outbreak of gun violence in California, killing at least 14 people.

The violence began around 11am at the convention building, Inland Regional Centre, where employees with the county health department were attending a holiday event, CNN reports.

Witnesses say at least two shooters opened fire, resulting in 17 people with serious injuries and many other wounded by bullets from automatic-style rifles.

The shooters were said to have escaped in a black sport utility vehicle (SUV), leading to a strong police response in the area.

Meredith Davis with the Bureau of Alcohol Tobacco and Firearms and Explosives told CNN affiliate KCAL/KCBS that a device that looked like a bomb also flew out of the vehicle when police pursued.

According to Jarrod Burguan, San Bernadino police chief said the shooters involved in the violence have been killed in a duel with the police.

The police said the main shooter has been identified as Syed Farook, who was initially suspected to have carried out the operation.

Tashfeen Malik, reported to be Farook’s girlfriend was also killed by the police in the shootout.

Farhan Khan, the brother-in-law of the suspect Syed Farook, told reporters that had “no idea why he would he do something like this. I have absolutely no idea. I am in shock myself.”

With over 352 mass shooting in the US in 2015, according to Washington Post’s tally, President Barrack Obama has called for gun control laws.

“We don’t yet know what the motives of the shooters are but what we do know is that there are steps we can take to make Americans safer,” Obama said in the interview.

“We should never think that this is just something that just happens in the ordinary course of events because it doesn’t happen with the same frequency in other countries.”

Obama said the pattern of US mass shootings “has no parallel anywhere else in the world”.