WALNUT CREEK (CBS SF) — Police and CHP had their hands full in Walnut Creek Monday evening after a group of protesters splintered off of a larger peaceful march, blocking traffic on I-680 and damaging property downtown.

Authorities in the North Bay and on the Peninsula were also busy early Monday evening as protesters blocked lanes of U.S. Highway 101.

READ MORE: Growth of Willow Fire Near Big Sur Slows Overnight, Still Zero Percent Contained

The California Highway Patrol said Interstate Highway 680 in Walnut Creek was blocked in both directions just before 6 p.m.

It appeared a splinter group of protesters split off from an earlier, largely peaceful march of about 1,000 people through downtown Walnut Creek. They entered I-680 at the North Main Street exit and spread out across all lanes of the freeway. Police and CHP officers were seen confronting the demonstrators and using flash-bang devices.

After about 45 minutes the freeway was reopened.

Warning: Explicit Language

After the freeway was cleared, some protesters damaged property in downtown Walnut Creek, police said.

Officers were dispersing the alleged vandals at 6:55 p.m. as well as others refusing to obey the curfew that started at 6 p.m.

READ MORE: UPDATE: 1 Dead, 6 Wounded in Saturday Evening Shooting at Oakland's Lake Merritt

Police said officers have made several arrests. According to police, some officers and demonstrators suffered minor injuries.

Earlier, Santa Rosa police tweeted about the protesters blocking northbound lanes of US Highway 101 shortly after 5:15 p.m. Drivers were advised to avoid Highway 101 until further notice.

The protesters cleared the freeway by shortly before 6 p.m.

In East Palo Alto, CHP shut down the University Avenue freeway entrances and exits after protesters marched onto US Highway 101, briefly blocking lanes in both directions.

The KCBS Traffic Twitter account tweeted about the freeway being blocked at 4:45 p.m.

About a half an hour later, the account posted that the protesters had left the freeway and traffic was moving again.

MORE NEWS: San Francisco Police Arrest Suspect In String Of Brazen Mission District Pharmacy Retail Thefts

The peace protest was in contrast to the closure of Highway 101 in San Jose on Friday, when some protesters smashed windows of vehicles that were stuck in the traffic gridlock the marchers created that afternoon.