Security footage of the incident shows three patrons dining at the La Creme Cafe on Melrose Avenue around 5 p.m. when two people wearing hoodies and at least one displaying a handgun approach.
One of the suspects appears to check the pockets of one patron while the other rifles through a purse and shopping bags on the table as the visibly shaken diners are seated.
One woman drops her cell phone on the ground before a suspect picks it up and puts it in a bag. The robbery lasted less than 20 seconds before the suspects fled.
The Los Angeles Police Department said no injuries were reported.
The cafe owner, who provided the footage to Fox News said via text message: "I realize all those [sic] news will reflect negatively on my business. Although… Silence will not help anyone."
"The mayor and the governor need to step up and let the police do their job PROPERLY," he added.
Fox Los Angeles reported one of the suspects has been arrested.
The busy area around Melrose Avenue has been plagued by crime, the cafe owner said.
Last month, a sneaker store employee was killed during a dispute over a raffle a few blocks from the cafe. Jayren Bradford was fatally shot outside the Shoe Palace after he tried to defuse an argument between a group of people.
A 16-year-old suspect was arrested the next day.