Utica College in upstate New York ordered students to shelter in place on Monday because of a "real, credible threat," the college said on Twitter without giving more details.
Armed law enforcement officers were evacuating buildings and taking people on campus to a safe location, the college said.
The lockdown came after two phone calls were made threatening the college's Gordon Science Center, Utica's WUTR-TV news station reported. There were no immediate reports of actual violence.
School and police officials did not immediately respond to requests for more details. The college is in Utica, a small city close to Lake Ontario.
(Reporting by Jonathan Allen in New York; Editing by Jonathan Oatis)