Three men are killed and four wounded in a shooting at a bowling alley in the Los Angeles suburb of Torrance and police say they are searching for a suspect or suspects.

A 28-year-old former Marine opened fire in a California country music bar packed with college students, killing 12 people including a police officer as dozens of terrified youngsters stampeded towards the door, authorities said yesterday.

A gunman shot a sheriff’s deputy and around six other people inside a country-and-western bar and dance club in Southern California on Wednesday night, authorities say.

A man went on a shooting rampage in California on Wednesday, killing five people including his wife, before taking his own life.

A gunman carrying a semi-automatic weapon and two handguns opens fire at multiple locations across a small Northern California community, killing four people before he was slain by police.

A friend of one of the San Bernardino attackers has been charged in connection with the mass shooting that killed 14.

One of the shooters in the San Bernardino massacre, Tashfeen Malik, sent at least two private messages on Facebook to a small group of Pakistani friends in 2012 and 2014, pledging her support for Islamic jihad and saying she hoped to join the fight one day.

Investigators believe the married couple who massacred 14 people in California last week - a US-born husband and his Pakistani wife - had been radicalised "for quite some time," but no clues pointing to an international plot have yet emerged, the FBI said on Monday.

US President Barack Obama lays out the most sweeping defense yet of his strategy to defeat Islamic State, but he offered no US policy shift to confront what he called a "new phase" in the terrorist threat after a mass shooting in California.

President Barack Obama says the US "will not be terrorised" by Wednesday's mass shootings in San Bernardino, California.

The mass shooting in California is being investigated as "an act of terrorism," the FBI said, amid reports the female assailant had pledged allegiance to the Islamic State group on Facebook.

Lawyers representing the family of the two San Bernardino attackers say, relatives are "in complete shock" over the shooting.

A US-born Muslim who along with his wife gunned down 14 people in California may have been radicalized and had been in contact with known terrorism suspects, news reports say.