A type of online attack known as "ransomware" has hobbled the San Bernardino City Unified School District's computer system, authorities announced Sunday.
"A ransomware attack has directly impacted the (SBCUSD) computer network and has locked access to District files," district officials said via social media. "We are working non-stop to correct the problem."
It was not immediately clear what information was affected, and how the district plans to proceed.
"Student and parent data is secure," according to the statement.
But attendance will be taken manually, and emails with students and staff "will not be possible until the situation is resolved," the district said.
School phone lines remained operational, officials said. Nutrition services and transportation were not expected to be affected by the cyber attack.
In ransomware attacks, hackers generally break into a computer system, steal or encrypt data and then demand the victim pay a ransom in order to get the information back.
Further details were not available Sunday evening.