Model and actor Tyson Beckford, and Black Eyed Peas member Apple de Ap were inside the pre-VMA party hosted by Brown and told TMZ they had heard four shots being fired at around 1.30am today local time.
Black Kapital Records CEO Knight was said to have walked out of the club, where he was spotted by a police officer and taken to hospital by ambulance.
He was reportedly shot twice, injuring his stomach and arm, and is now undergoing surgery.
The suspected gunmen were apprehended by police, as officers searched the nightspot for clues and quizzed revellers over the events of the night.
Roads around the nightclub were immediately sealed off by police, as the nightclub was evacuated, with several partygoers detained for questioning.
Police lines are set up outside the 1OAK club, in West Hollywood, California. Photo / AP
Guests at the event had also included singer Justin Bieber and rapper The Game.
Katie Clendon, thought to have been inside the club, said via her Twitter account that she thought Brown had been the intended target.
'Literally can't believe what I just witnessed. Someone tried to fire shots at Chris Brown at 1oak. Speechless.'
She added: 'Prayers to all those harmed by this. Honestly still in disbelief this happened.'
In the moments after the shots were fired, Brown was seen climbing onto what appeared to be a bar in the nightclub, apparently angrily remonstrating with other clubgoers as a bouncer told partygoers to 'Get down'.
At around 5:45 a.m. LA time, Brown tweeted about the incident.
'It's disappointing that we as a society can#t have fun or enjoy ourselves without any altercations sometimes. Miss me with the bullsh*t!!!' he tweeted.
Australian model Simone Holtznagel revealed she was at10AK's Pre-VMAs party when the shots were fired.
The former Australia's Next Top Model finalist took to social media to reveal she and fellow model friend Chloe Lloyd were within the vicinity, with Chloe also sharing the fact that the pair sought cover in a toilet cubicle when the incident occurred.
'Me and @MOANNN sort refuge in a toilet cubicle as rifles targeted Chris brown & bieber outside. #usa, (sic)' Chloe wrote on her Twitter account, tagging Simone in the social media post.
A controversial figure, Knight is no stranger to the effects of gun violence.
His friend Tupac Shakur was shot multiple times during a drive-by shooting in Las Vegas in September 1996, although during a previous visit to 1OAK in May, Knight told reporters that no one had ever been charged with Shakur's murder because he wasn't really dead, and was instead living on an island.
Knight also suffered a gunshot wound to the leg during a shooting at a 2005 pre-VMA party, hosted by rapper Kanye West.
Owned by New York-based Butter Group, the Los Angeles branch of 1OAK - which stands for One Of A Kind - is a spin off of the New York club, while there are further branches in Las Vegas and Mexico City.
The club, which bills itself as 'Bringing a New York nightclub experience to Los Angeles' has been open on the famous Sunset Strip since the start of the year and has proved popular with many celebrities, including Leonardo DiCaprio and Rihanna.
Last night's party at the club was a precursor to tonight's MTV Video Music Awards, which takes place from 6pm local time at LA's recently redeveloped Inglewood Forum.
- Daily Mail
