Harvard University has ordered the evacuation of four buildings on the Cambridge, Mass. campus after receiving reports of explosives at the sites.Just after 9:30 a.m. today (Dec. 16), the university posted the following on its web page:

The Harvard University Police Department (HUPD) this morning received an unconfirmed report that explosives may have been placed in four buildings on campus:  the Science Center, Thayer, Sever and Emerson Halls. HUPD and Cambridge Police are on the scene. Out of an abundance of caution, the buildings have been evacuated while the report is investigated.  Harvard's focus is on the safety of our students, faculty and staff.

Harvard is also putting updates on its official Twitter feed.

Update: HUPD/Cambridge Police on scene. Unconfirmed report that explosives may have been placed in 4 campus buildings http://t.co/dr5PFJr2Is

— Harvard University (@Harvard) December 16, 2013

Alert: Reports of bombs placed on campus are unconfirmed. There have been NO reports of explosions. View for updates: http://t.co/gAWVUFoPtp

— Harvard University (@Harvard) December 16, 2013

Alert: Unconfirmed reports of explosives at four sites on campus: Science Center, Thayer, Sever, and Emerson. Evacuate those buildings now.

— Harvard University (@Harvard) December 16, 2013