The Gorham and Portland campuses of the University of Southern Maine have been evacuated following a bomb threat at 4:10 p.m. Monday.

Bob Caswell, a university spokesman, said a call, threatening bombs on both campuses, was received at the library in Bailey Hall on the Gorham campus. Caswell said all classes were canceled for the evening.

He said this threat marks the sixth this semester at the university. The first came on Oct. 2, Caswell said. He said a recent reward offer hadn’t resulted in any arrest.