A confrontation in downtown Los Angeles late Thursday between police and Occupy L.A.protesters appeared to have stemmed from a sidewalk chalk-drawing demonstration, witnesses said.

At least two officers were injured and several arrests had been made.

A woman who identified herself as part ofOccupy L.A. said protesters attended the monthly L.A. ArtWalk on Thursday night with the intention of showing support for people previously arrested for chalking on the sidewalk. A Facebook event advertised the planned demonstration.

Discuss at 9 a.m. Friday: Skirmishes at L.A. ArtWalk

Some of the messages written at the intersection of Spring and 5th streets included, “May the youth rise” and “End the Fed.”

“We were handing out free chalk for freedom of speech,” said Cheryl Aichele, 34, a member of Occupy L.A.

Police arrived at the intersection shortly before 10 p.m. to move protesters blocking the street. At one point, an unidentified man tossed a glass bottle over his shoulder that landed in front of a line of LAPD officers gathered on Spring Street between 4th and 5th streets. The man was shot with what appeared to be a non-lethal weapon, witnesses said.

PHOTOS: The ArtWalk confrontationPolice used batons and non-lethal projectiles to disperse the crowd, which in turn threw bottles and cans at officers and chanted, “Whose streets? Our streets!”

Hundreds of officers in riot gear systematically moved the crowd away block by block as people gathered in the windows of nearby apartments and bars to watch and snap cellphone pictures. It took officers about two hours to quell the protest.

“I came down for ArtWalk and it turned into this,” said 25-year-old Susan Enciso.

melissa.leu@latimes.com

stephen.ceasar@latimes.com

Times staff writers Andrew Blankstein, Kate Mather, Paul Pringle and Matt Stevens contributed to this report.