Screenshot via KTLA.

Screenshot via KTLA.

The Los Angeles Police Department called a citywide tactical alert Sunday, after protesters of the George Zimmerman verdict blocked the Santa Monica (10) Freeway.

Demonstrators carrying a large picture of Trayvon Martin entered the eastbound lanes near the Crenshaw on-ramp in the Mid-City area, as LAPD and California Highway Patrol crowd control officers formed a riot line.

Officers fired less-lethal beanbag rounds at the crowd after they were struck by rocks and batteries, reports the Los Angeles Times. Several protesters were arrested after they brought traffic to a standstill for about 20 minutes, reports KTLA.

In Oakland, protesters took to the streets Saturday night following a Florida verdict that acquitted Zimmerman of murdering Martin, reports the Oakland Tribune. A BART police car was reportedly spray painted and had its windows smashed.

Protests were peaceful in Sanford, Fla., where Zimmerman fatally shot Martin at a gated community on Feb. 26, 2012. Seminole County Sheriff's patrol vehicles blocked access to the courthouse, redirecting protesters following the verdict, reports the Orlando Sentinel.