In the afternoon, hundreds of pro-Israeli and pro-Palestinians demonstrated on opposite sides at the intersection of Wilshire Boulevard and Veteran Avenue.
The men who were detained were traveling in a pickup truck.
One of the men in the truck, who was not taken into custody, said he jumped out to retrieve a Palestinian flag that a demonstrator ripped from his friend's hands and knocked to the ground.
A video posted on the Jewish Journal website shows the scuffle.
Moments later, an officer fired at the pickup truck.
"I was able to see the truck leaving and there was an officer had a gun toward the truck and he just fired toward the truck," said Hany Refai, a protestor.
The situation became tenser when protestors spilled into the streets, causing police to block traffic and officers in riot gear to move in.
Demonstrators were asked to leave the area. At about 11 p.m., traffic was still being diverted from the area.
The Los Angeles County Sheriff's Department was handling investigation.