Two people have been killed and six injured in a mass shooting at a warehouse party in Los Angeles over the weekend.

The unlicensed event was taking place in downtown Los Angeles on Sunday evening, before being shut down by police at around 11 PM when officers spotted a person, thought to be armed with a gun, enter the building.

LAPD officer Norma Eisenman said that the person was arrested at the scene, and the party was closed down. Around two hours later at 1 AM, police were called back to the scene following reports of gunfire.

According to police, someone opened fire outside the warehouse, subsequently shooting eight people – two fatally. One man in his 20s was pronounced dead at the scene, while a woman in her 50s later died in hospital.

Six other people were injured in the shooting, police said. LA Mayor, Karen Bass, called it a “senseless” act of violence, explaining: “The loss of life is devastating and those who are responsible must be held accountable.”

“There will be no tolerance for violence in this city. My thoughts are with the victims and their families. We will continue to work together to keep LA safe.”

No suspects have been identified as of yet, though a police investigation is currently underway.

The event was originally suspected to be an unofficial afterparty for LA’s annual HARD Summer Festival, though it has since been reported that it was thought to be a "local gang celebration". A representative for the LAPD also stated that the event was "not related to the festival".

Police called the warehouse party an “unsanctioned gathering”. Anthony Rodriguez, president and chief executive of the Fashion District business improvement district where many of these events are said to go ahead, commented that “nothing good comes of these parties.”

“Not only are they unpermitted, so there’s no safety protocols… we know there’s alcohol consumption, illegal drugs, underage drinking and prostitution coming out of these parties. And now violence.”