(VOVworld) – The Department of Homeland Security (DHS) said the US has no credible information indicating an imminent attack on American soil, a US security official said on Monday after an Islamic State video threatened to strike Washington.

DHS Secretary Jeh Johnson, seen in screen shot, answers questions from Congressman Beto O'Rourke at Homeland Security Committee hearing. (Photo: c-span.org)

Islamic State warned in a new video that all countries taking part in air strikes against Syria will suffer the same fate as France. The US Defense Department has banned US troops and employees from traveling in their free time within 50 kilometers of Paris.

In another development, four buildings at Harvard University were evacuated after the school received an unconfirmed bomb threat on Monday. Units were deployed to the scene to search for a bomb and prepare for an emergency situation.