There was an officer-involved shooting, according to police.
The suspect is understood to be among those injured.
Local reporter Bill Melugin tweeted: “We were at a DUI checkpoint with LAPD and heard all their radios going crazy about a man with a machete and gas mask in Canoga Park.
“Then shots fired call and officer needs help call came over radio, followed by suspect not in custody. We are en route now.”
The incident reportedly occurred in LA’s Canoga Park area.
Mr Melugin later tweeted: “Just spoke to a resident. He heard at least five gunshots. Said he thought it was a pursuit, saw several LAPD units come flying down street, turned a corner, then ‘bam bam bam bam bam’.”
The news has come as the US is on high alert after the FBI earlier this week arrested a former marine over alleged plans to launch a terror attack on Christmas Day.
Federal agents arrested Everitt Aaron Jameson, a 26-year-old Islam convert, in San Francisco, California.
It is claimed Mr Jameson said “Christmas was the perfect day” for a terror attack in San Francisco and “did not need an escape plan because he was ready to die”.
Officials said the suspect was talking to an undercover FBI agent and added that the tow truck driver was arrested earlier this week.
FBI documents allege he posted and liked pro-ISIS and pro-terrorism content on Facebook – which is what alerted him to authorities.
A source flagged the content to the FBI and Mr Jameson spoke to the source and an agent – who he thought were both high-ranking members of a terror group – between October and this week.
More to follow…