City IT staff called it a cyberattack in emails, but Mayor Mike Wiza said the cause was unconfirmed. Employees also lost access to shared files and software.
A hacking group claims it accessed FBI systems. The bureau has not confirmed a breach, while its recruiting website and applicant portal have been unavailable.
Spokane Public Schools took PowerSchool, payroll and other services offline while teachers shifted to manual workarounds and an outside expert investigated.
City officials said the attack was contained without significant operational effects and approved replacement modems with additional security controls.
