SASEBO NAVAL BASE, Japan — Officials at Naval Base Guam were taking precautions Monday after a bomb threat was called into 911.

The threat led Navy officials to immediately increase security measures at all base entry points, spokeswoman Annette Donner wrote in a statement. There were no building evacuations, only “normal security precautions.”

The incident remains under investigation, Donner said. Base entry will be slowed until further notice as K-9 units search vehicles and security officials double-check identification cards.

“We take these things seriously,” Donner said.