No suspicious package found in Facebook HQ at Menlo Park: Police

A bomb threat prompted authorities on Tuesday to evacuate a building at the Silicon Valley headquarters of Facebook, police said, but gave the "all clear" after an hours-long search turned up no sign of a device.

"The San Mateo County bomb unit was dispatched with explosive detection dogs that conducted a sweep of the building and found no suspicious packages or devices," they said.

"The building is all clear and secure," the police added.

Everyone is safe and the company is looking into the incident, the spokesman said in an emailed statement to Reuters.

Menlo Park Police Department said a building at 200 Jefferson Drive has been evacuated and the bomb units are on the scene going through the building.

However, it did not specify which Facebook building in Menlo Park was evacuated.

YouTube was another Silicon Valley company that faced security threat in the recent past. In May, a woman opened fire at YouTube's headquarters in San Francisco, wounding three people before she shot herself dead.