(CNN) — [Breaking news update at 3:31 p.m. ET]
All four Harvard University buildings evacuated after unconfirmed reports of explosives have been cleared and reopened, the school said on its website Monday afternoon.
(CNN) — A bomb threat prompted officials to evacuate four Harvard University buildings Monday morning on a day of final exams, the Boston-area school said.
No explosions were reported, and authorities declared three of the buildings safe before 2 p.m. While law enforcement personnel still were checking the fourth building, two law enforcement sources told CNN late Monday morning that the threat appeared to be a hoax.
The morning’s final exams in the affected buildings were canceled or postponed because of the report, student newspaper The Harvard Crimson reported, citing university officials.
The school said around 9 a.m. that it was evacuating three academic buildings — the Harvard Science Center, Sever Hall and Emerson Hall — and a freshman dormitory, Thayer Hall, because of an unconfirmed report that bombs had been placed there.
“Out of an abundance of caution, the buildings have been evacuated while the report is investigated,” Harvard said on the emergency page of its website. “Harvard’s focus is on the safety of our students, faculty and staff.”
All but the science center were declared safe by 2 p.m., according to the school.
Harvard University and Cambridge police were investigating. The bomb report was made by phone, and the FBI is also among the investigating agencies, a law enforcement official told CNN.
Some students were taking final exams in the affected buildings when the evacuations were ordered, said student Sam Weinstock, incoming president of The Harvard Crimson.
At least some of the evacuees were taken to a freshman dining hall, where they were told their Monday morning exams would be called off, Weinstock told CNN.
Elsewhere on campus, Weinstock said, students were “more or less going about their days.”
The school notified the campus community of the evacuations through its emergency alert system, which includes text and e-mail messages, Weinstock said.
Harvard’s final exams for the fall term began last week and are scheduled to go through Friday.
Around 11 a.m., Cambridge police said they were opening roads around Harvard Square, the Cambridge commercial center near Harvard’s campus. The square had been shut down because of the report.
CNN’s Deborah Feyerick, Susan Candiotti, Alexandra Field and Shimon Prokupecz contributed to this report.