At least 13 people, including a police officer were killed, at the Borderline Bar and Grill in Thousand Oaks, west of Los Angeles last night.
The shooter stormed the Borderline Bar and Grill, wearing a black trench coat and armed with a pistol equipped with an extended magazine and smoke grenades, and began targeting people as young as 18.
Among those killed was a Ventura County sheriff sergeant called Ron Helus, who was responding to the emergency call.
Around ten to 15 more victims were thought to be injured during the mass shooting, including a bouncer, a young female cashier and college students.
Witnesses and survivors comfort each other as they stand near the scene of the shooting at the at the Borderline Bar and Grill in Thousand Oaks, California, last night
Las Vegas police stand guard along the streets outside the festival grounds of the Route 91 Harvest last year after the shooting which saw 59 people killed
A Ventura County Sheriff’s Office official said around 30 shots were fired inside the building.
The gunman then shot himself before police got inside the popular country music venue.
He was seen dressed in all-black, wearing a baseball cap, sunglasses and a mask covering the bottom part of his face when he arrived at around 11.20pm.
Chandler Gunn, from nearby Newbury Park, Ventura County, California, was told about the deadly killing by his mom.
The 23-year-old rushed to the bar, which holds college country music nights on Wednesdays, where he called a friend who was also at the Route 91 Harvest music festival in Las Vegas when a gunman opened fire, killing 59 people and wounding hundreds.
Gunn was told some type of tear gas was thrown into the bar with smoke across the bar and gunshots ringing out, as many revelers ran out the back door towards nearby apartments for safety.
Some witnesses in the bar were forced to use bar stools to break windows and escape, authorities said.
Gunn added: ‘A lot of people in the Route 91 situation go here. There’s people that live a whole lifetime without seeing this, and then there’s people that have seen it twice.’
Police officers guard the road leading to the Borderline Bar and Grill. The killer shot himself before police were able to get inside the building
He hasn’t been able to contact his friend again but knows she is safe, he told the Los Angeles Times.
The Route 91 festival in Las Vegas was also a country music event and attracted many of the same audience and the mass shooting on October 1, 2017, was the worst in US history.
Gunman Stephen Paddock opened fire through the windows of his suite at the Mandalay Bay hotel which overlooked the open air concert.
Another witness to last night’s atrocity said he had multiple friends at the Borderline bar who were also survivors of the Route 91 Harvest shooting in Las Vegas.
He told ABC7 California TV station: ‘A lot of my friends survived Route 91. If they survived that, they will survive this.’
Many inside the bar had to throw bar stools to break the windows and escape as the gunman opened fire
The Borderline bar is described as the county’s ‘Largest Country Dance Hall & Live Music Venue’ and boasts of 2,500 sqft of open dance floor, with pool tables, games and flat-screen TVs.
Savannah Stafseth, who was outside on the patio when the shooting started, told the LA Times: ‘There are no words. Those are my people. It’s just not fair. It’s not fair. All these people after Route 91. It’s not fair.’
Thousand Oaks is known as an area with low crime and is considered one of the safest cities in America.