Bomb threat prompts evacuation of Stanford business school

A bomb threat prompted the evacuation of Stanford University's Graduate School of Business on Friday morning, the San Francisco Bay Area school said.

The threat was reported by the school in an emergency notification around 11 a.m. PDT (2 p.m. EDT). The message said some 700 faculty and staff members in the Knight Management Center complex were affected, but classes were not in session at the time. The nature of the threat or where it came from were not immediately clear.

The school said police would sweep the campus for anywhere between 90 minutes to two hours for any sign of explosives. Several roads in the area were closed, though the rest of the university was unaffected, the school said.

Stanford said the decision to evacuate was made "out of an abundance of caution."