Three of the four buildings closed at Harvard after a Monday morning bomb threat have reopened, the university said.
Thayer Hall, a freshman dorm, and Sever and Emerson Halls, classroom buildings, reopened early Monday afternoon, the school announced. Harvard Yard also reopened. The Science Center remained closed, Harvard said on its website.
The four buildings were evacuated and final examinations in them were canceled when Harvard issued the alert shortly after 9 a.m. on its website, on Twitter and in emails. The alerts cited "unconfirmed reports of explosives at four sites on campus: Science Center, Thayer, Sever, and Emerson. Please evacuate those buildings now."
The school, in Cambridge, Mass., tweeted that there had been no explosions. Faculty, staff and students were being updated through the school's website, email, voicemail and internal messaging system. Access to Harvard Yard, the historic center of campus, for several hours was limited to those with Harvard ID cards.
"Out of an abundance of caution, the buildings have been evacuated while the report is investigated," the website statement said. "Harvard's focus is on the safety of our students, faculty and staff."
University and Cambridge police were being aided in the investigation by state and federal officials, the school said.
President Obama, a Harvard Law School graduate, was briefed on the situation, the White House said.
The university tweeted that it was working to reschedule exams that had been scheduled for the affected buildings. Final exams have been taking place for several days, and scores of finals had to be canceled Monday.
Students Alexander Ryjik and Diego Abrahao said their professor was handing out exam booklets for their Politics of American Education class when the alert went out to leave Emerson Hall.
"I have a good guess somebody called it in so they wouldn't have to take an exam," Ryjik told the Associated Press. "It's frustrating because now the exam will have to be postponed."
If the bomb threats turn out to be a hoax, the person who made them could face up to 20 years in prison, Boston criminal defense attorney Andrea Lance, a former Miami-Dade prosecutor, told USA TODAY.
"It's a crime against the public peace," Lance said. "You're not only disrupting people's lives, but you're using emergency services and you are causing fear."
"Police have to respond as if this is real. It takes a lot of resources," Lance said. "When the threat comes in, you don't know who is behind it. Is this a kid who wanted to get out of final exams or is this something like the Boston Marathon bombing last year?"
Jay Harris, dean of undergraduate education, told students gathered at Harvard's Annenberg Hall, the freshman dining facility, that Monday morning final exams had been canceled due to the scare, the Crimson reported.
"Following announcement, students erupt in applause," the Crimson tweeted.
The main campus of the school, among the nation's most prestigious, sits on 210 scenic acres along the banks of the Charles River. Harvard's student body includes about 6,700 undergraduates and another 14,500 graduate and professional students.
The Associated Press