(Portland, OR) -- School districts in at least five Oregon counties responded to bomb threats on Monday. Law enforcement in Marion, Multnomah, Clackamas, Linn and Coos counties are investigating incidents in the Cascade, Colton, Central Linn, Corbett, Coos Bay and Bandon school districts. The FBI's Portland field office released a statement acknowledging it's working with state and local partners to "ensure safety" and urged any schools receiving threats to call 911 or the Portland FBI office.