BART service has also resumed between Castro Valley and Dublin/Pleasanton after stopping service as a result of the police activity, the agency said.
The eastbound direction of the freeway remains closed. Traffic is being diverted off at Eden Canyon Road.
There are no further details at this time.
BART service was previously impacted earlier between the Castro Valley and West Dublin stations around 10a.m. Saturday, when a pick-up landed near the BART tracks.
Then, the transit agency announced around 1p.m., it resumed service, before stopping service again due to the police activity.
Bay City News contributed to this report.