Reports suggested that there were explosives found at the campus. The University even issued an alert on its website [read here] saying that people must evacuate the building after unconfirmed reports of explosives were doing the rounds.
The University even tweeted saying-
<blockquote class="twitter-tweet blockquote" lang="en"><p>Alert: Reports of bombs placed on campus are unconfirmed. There have been NO reports of explosions. View for updates: <a href="http://t.co/gAWVUFoPtp">http://t.co/gAWVUFoPtp</a></p>— Harvard University (@Harvard) <a href="https://twitter.com/Harvard/statuses/412589684213448706">December 16, 2013</a></blockquote> <script async src="//platform.twitter.com/widgets.js" charset="utf-8"></script>
While some reports suggested that the explosives were found later, it was however not yet confirmed by the authorities. University and local police authorities were investigating the matter.
The buildings - the Science Centre, Thayer, Sever and Emerson halls - were ordered to be evacuated in response to information received by police, the university said in a statement posted on its emergency alert site.
Fire fighters were also seen at the campus.
(With agency inputs)