At least 12 people are dead after a gunman opened fire at a country bar in Thousand Oaks, California overnight.
Thousand Oaks is around 55km north-west of Los Angeles.
Around 200 people were inside the bar, which was hosting a university night, when the shooter began firing.
No motive for the shooting has been found, with police saying they found the suspect dead inside.
He has been identified as 28-year-old Ian David Long, a US Marine Corps veteran.
Police say Mr Long forced his way into the bar after shooting the bouncer, before tossing a smoke grenade into the packed bar and opening fire.
Ron Helus, a Ventura Sheriff's Sergeant, died in hospital after entering the active scene and being shot several times.
US President Donald Trump tweeted called it a "terrible" event, but praising the "great bravery" shown by police officers.