SAN FRANCISCO—Businesses across San Francisco are putting up plywood outside their storefronts and temporarily closing in preparation for potential unrest following election day, no matter the outcome.

Earlier this summer, protests in support of Black Lives Matter and Antifa quickly turned violent across cities in the United States. Just two weeks ago, a Trump supporter and free-speech organizer was attacked by an Antifa member while peacefully protesting. A new poll released by UC Berkeley surveyed Californian voters, and found that more than 5 in 10 Trump supporters believed that post election violence was “very likely”, compared with 4 in 10 Biden supporters. Overall, the survey reported that 44% of California voters believed post-election violence was “very likely”, while another 44% said it was “somewhat likely” and 12% said it was “not likely”.

The city’s police department has also been making preparation in advance for election night. The San Francisco Police Department (SFPD) announced that they’ve canceled vacation days and time-off for officers in order to have more cops patrolling the streets, and will have officers on stand-by if any violent or spontaneous events erupt.

Police and intelligence agencies said there is no known threat yet, but that businesses are boarding up out of an abundance of caution to avoid costs that may become associated with damage or theft.