Vandals severed a number of fiber optic cables on Thursday, leaving thousands of people in Santa Clara, Santa Cruz and San Benito counties without cell phone, Internet and landline service, police said.

San Jose police said there is evidence that someone removed a manhole cover and severed a number of cables. Police said the incident is being investigated as vandalism.

AT&T says it's aware of a cut in the area and has repair crews out.

Verizon Communications spokesman John Davies says about 50,000 of its landline and Internet customers are without service, mainly in the Morgan Hill and Gilroy areas.

"Our concern is 911. If someone is having an emergency and can't make a phone call, they should go to the nearest firehouse, police station or hospital emergency room," Santa Clara County spokeswoman Joy Alexiou said. "We have people at those areas with radios."

Alexiou said the sheriff's department has doubled patrols since the outage.