The so-called "Chalk Walk" invited participants to meet on Spring Street at about 7:30 p.m. and "come decorate" with free chalk.
According to DowntownLAblog, the tensions began when a woman was arrested soon after for writing with chalk on the sidewalk.
Police arrived at the intersection near Fifth and Spring streets to disperse crowds gathered there.
The Los Angeles Times reports officers pushed the crowd back with the authority to use rubber bullets, bean bags and batons.
The crowd threw bottles and cans at officers, screaming and chanting.
Four officers received minor injuries in the melee, along with many of the protesters.
OccupyLA maintains chalking is a legal form of free expression, while an LAPD spokesperson defended such arrests as vandalism.
LAPD chief Charlie Beck said Friday, "I want to make sure people understand that if you throw rocks and bottles at police officers, if you fail to disperse when police officers tell you to do so, if you deface private or public property, you will be arrested."
OccupyLA protesters have been pitching their tents most recently outside the Central City Association headquarters on Wilshire Boulevard in Downtown Los Angeles.
According to the group's Facebook page there have been numerous arrests recently for chalking on public property.
The Los Angeles Times quotes an Occupy LA member as saying the police may have been trying to get OccupyLA away from the Central City Association building.
Chalk artists have a highlight of the last two Echo Park Artwalks.
Do you think chalk writing is a legal form of artistic expression and should be protected?