An email warning of explosives planted in four buildings on Harvard University's Cambridge, Mass., campus led to the buildings' evacuation Monday, police said. Authorities reported that no explosives had been found in the Science Center, Sever, Emerson, and Thayer halls as of mid-morning, although they said police from at least five different agencies assisted by bomb-sniffing dogs were still conducting searches, the Boston Globe reported. On the university's website, Harvard officials said the unconfirmed report of explosives prompted the evacuation of the four buildings "out of an abundance of caution." In an email, Dean of Freshman Thomas Dingman said final exams scheduled for Monday morning in Science Center, and Emerson and Sever halls were canceled. Finals are this week for undergraduates. Thayer Hall is a freshman dorm. "Access to Harvard Yard has been restricted to residents of the yard with Harvard ID," the website message said. "As of the writing of this message the report remains unconfirmed and the HUPD [Harvard University Police Department] has no reason to believe there is a threat to any other site on campus." Graduate student Nathan Pflueger told the Globe he had just arrived at his Science Center office when the alarm sounded. Police immediately told people it would be a while before the building would reopen, he said. "My guess is someone is trying to cause mischief during finals week," Pflueger said.