OAKLAND (AP) — Protesters who chained themselves to trains Friday stopped service from Oakland to San Francisco and shut down a major station in the Bay Area Rapid Transit system days after a grand jury in Ferguson, Missouri, declined to indict an officer in the shooting death of an 18-year-old.

Some of the roughly 25 protesters have been arrested, but it is unclear how many. They first held train doors open and later chained themselves to each other and to the trains on both West Oakland station platforms, BART spokeswoman Alica Trost said. Trains run from those platforms into San Francisco and into the suburbs to the east.

No injuries have been reported. BART police were on scene, but Trost said she does not have information on when the trains will be running again.

Buses are running through the Transbay Tube and into San Francisco, Trost said.

Demonstrations in Oakland have persisted since a grand jury on Monday declined to indict Ferguson Officer Darren Wilson, who is white, in the Aug. 9 killing of Michael Brown, who is black.

Since then, some protesters have smashed the windows of businesses, blocked freeways, sprayed graffiti and set trash cans on fire. Police have arrested 167 people, and there could be more after officers review video and pictures of the protests, Oakland police spokeswoman Johnna Watson said.

Groups nationwide are protesting on Friday as an economic boycott to further draw attention to their anger over the grand jury’s decision. A large protest against spending money on Black Friday was slated to start in West Oakland and end at a Walmart store several miles away.