BART service between the South Hayward station and the Berryessa station in San Jose resumed Friday afternoon following an hours-long shutdown that the agency said was caused by apparent vandalism.

In an update posted around 2:15 pm., the agency said Orange Line service has been restored between Richmond and Berryessa, while Green Line trains from Daly City are only going as far as South Hayward.

The agency first issued a service advisory about the issue around 5:20 a.m., which they said involved an equipment problem.

BART spokesperson Chris Filippi told CBS News Bay Area, "We have crews on the scene and additional staff responding at this point to make repairs and to gather more information on exactly what happened."  

In an update posted around 11:30 a.m., BART said the cause of the disruption was an "apparent act of vandalism" near the Hayward maintenance yard  that resulted in a fiber being cut.

"The fiber cut prevents BART from being able to safely run trains," said a statement on the agency's social media.

Other parts of the system in the East Bay, San Francisco and Peninsula were not affected. During the shutdown, the agency sent extra staff to help at stations with no train service, while AC Transit provided free mutual bus service connecting impacted stations between Hayward and Milpitas.

Friday's incident follows several other high profile service disruptions in recent months. Last month, issues in the Transbay Tube on two separate Mondays led to major delays, while computer issues led to hours-long shutdowns of the system in May and September.

When asked about the recent issues, Filippi noted that the customer on-time rate remains over 90% even after the disruptions.

"BART typically is a reliable service, but having said that, we have to acknowledge that even at over 90%, that doesn't matter this morning. That doesn't matter for folks who impacted by this major service disruption. We certainly apologize to those folks," he said.