WASHINGTON: FCC headquarters was evacuated this morning due to a bomb threat, a source within the commission confirmed. Speculation regarding the threat emerged as events were canceled. Notification went out around 11:20 a.m. Eastern that a round table on consolidated licensing was postponed.

Further speculation sped through various Twitter feeds, though nothing initially appeared on the FCC’s Web site nor its own Twitter page. The source within the Portals said some meetings were held on the grass before staff was dispatched.

“Several buildings cascaded into the threat warning,” the source said.

Details about the nature and timing of the threat were unavailable, though the source said staff was out for about two hours--the “longest ever,” and that bomb-sniffing dogs were dispatched. E-mail releases from the commission resumed mid-afternoon.

Bomb threats in Washington, D.C. are something of a regular occurrence. WTOP-FM reports that the Pentagon City Metro station was shut down briefly April 3 for a bomb threat. Another was reported at World Bank headquarters in January. -- Deborah D. McAdams