UPDATED: December 16, 2013, at 2:02 p.m.

With bomb threats in four buildings looming and affected morning exams cancelled, undergraduates evacuated from the Science Center and other buildings in Harvard Yard Monday morning congregated in common spaces throughout campus, awaiting news from law enforcement officials and administrators.

Thayer Hall resident Zachary M. Dinan ’17 was awoken by a blaring fire alarm around 9 a.m. Expecting to "be back in his bed in five minutes," Dinan did not even think to put socks on before leaving Thayer, which, along with the Science Center, Emerson Hall, and Sever Hall, was evacuated early in the morning following unconfirmed reports of explosives.

When he went downstairs and asked the police officer if there was an actual fire, the officer told him that “it was going to be a while.”

“He said to go to Annenberg and wait it out,” said Dinan.

Thayer was cleared later in the afternoon.

A. Viktor Wrobel ’17 was sitting in the Science Center awaiting the start of his Life and Physical Sciences A: “Foundational Chemistry and Biology” exam around 9 a.m. when the fire alarm went off and students were evacuated from the building.

“The policeman outside said, ‘Go find someplace warm, because you're not getting in anytime soon,’” Wrobel said

Wrobel added that he was “not too upset” because he appreciates the additional time to study, although he was “a little unsettled.”

“It would be nice to get some sort of notification about rescheduling or whether we can go back in or exactly what's going on," said Wrobel.

Former Undergraduate Council Vice President Jen Q. Zhu ’14 sent an email several top College administrators, including Interim Dean of the College Donald H. Pfister, Dean of Student Life Stephen Lassonde, and Secretary of the Administrative Board John “Jay” L. Ellison, asking for more information about exams and safe areas surrounding evacuated buildings with an email at 9:34 a.m.

“I'm one of the hundreds of students that have been evacuated from Thayer, Sever, Science Center, Emerson due to explosive threats—students appreciate the notifications informing us what's going on but want more specific instructions from the MessageMe and emails instructing what we should do, given the news,” wrote Zhu, who was scheduled to take an exam for Government 1510: “American Constitutional Law” in the Science Center at 9 a.m. She added in the email, which was also sent over the UC general list, that some students subscribed to MessageMe, Harvard’s emergency alert service, had not received text alerts.

In an interview with The Crimson Monday afternoon, Zhu said that she thought administrators had improved the University’s emergency communication system since the Boston Marathon bombings and manhunt in April, though she added that there is always room for improvement. She said she had been in contact with administrators from the Office of Student Life since sending the email.

—Bryan L. Bu and Mariel Klein contributed to the reporting of this story.

—Staff writer Madeline R. Conway can be reached at mconway@thecrimson.com. Follow her on Twitter @MadelineRConway.

—Check TheCrimson.com for updates.