Harvard University says all buildings clear after unconfirmed reports of explosives

Dec. 16, 2013: Students are seen at Harvard University after being evacuated over unconfirmed reports of explosives. (The Harvard Crimson)

Harvard University says all buildings are clear after four were evacuated on its Cambridge, Mass., campus earlier in the day over unconfirmed reports of explosives.

Students have been told that they can return to the Science Center, Thayer, Emerson and Sever Halls.

An alert posted on the university’s website shortly after 9 a.m. local time Monday had read “Unconfirmed reports of explosives at four sites on campus: Science Center, Thayer, Sever, and Emerson. Please evacuate those buildings now.”

There were no reports of explosions. A law enforcement source told Fox News that the threat came via email.

Bomb squad officers and police from the State, Cambridge, Harvard University, Boston and Transit departments investigated the scene, The Boston Globe reported, along with the FBI.

“Harvard's focus is on the safety of our students, faculty and staff,” the university's police department said in a statement. Some of the departments were using bomb-sniffing dogs.

Three of the buildings that were evacuated border Harvard Yard area of the campus.

The Department of Homeland Security also searched for explosives at the campus, but an official told Fox News that nothing had been found. A White House official said President Obama was briefed on the situation.

Final exams are ongoing at the school and were canceled in the morning, the Harvard Crimson student newspaper announced..

Students told a WFXT reporter that they were taking an exam when a fire alarm went off and they were told to evacuate.

“Something like this…is hard to believe,” Sean O’Neill, a student, told Fox News.

O’Neill said the university’s emergency messaging system was “very effective,” as students got multiple texts and emails alerting them to the situation.

Harvard University students go on winter break starting Dec. 21, according to a calendar posted on the university’s website.

There was also a report of a person with a firearm at nearby UMass Boston Monday afternoon, but police quickly confirmed it was not true.

"There were reports of a threat at @UMassBoston. There is no threat. False report. Scene is clear," the Massachusetts State Police said in a tweet.

Fox News' Catherine Herridge contributed to this report.