EAST BAY (BCN) — About 12,000 customers are without power tonight in San Leandro and Oakland as crews work to determine the cause and restore power, a PG&E spokesman said.

The power outage started at around 8 p.m. and multiple crews are working to restore service, spokesman J.D. Guidi said.

The outage caused a major delay on BART’s Fremont line until about 9 a.m. when normal service resumed, according to BART officials.

Another outage tonight is affecting 1540 customers in Millbrae and San Bruno in San Mateo County across San Francisco Bay.

That outage started at 6:37 p.m. and the cause has not been identified.

In both outages, PG&E officials won’t know when power will be restored until crews identify the cause, Guidi said.

Crews are working as safely and quickly as possible.