OAKLAND (CBS SF) – Protesters briefly blocked all lanes of Interstate 880 in Oakland Tuesday, generating a huge backup just before the evening commute.

Several dozen people walked onto the Jackson Street offramp a little after 3:00 p.m. causing a massive traffic jam. The event was captured on social media.

KCBS Radio reported that police were making progress clearing the scene but a backup continued in the area, including the Webster St. tunnel to Alameda. Our traffic map showed a heavy backup in the area.

The shutdown comes as Bay Area cities participate in a day of action calling for an end to police brutality in the United States.