PORTLAND, Ore. -- A Portland State University student reported being assaulted by a man who said he had a gun on campus Monday night.

The student was at the Branford Price Millar Library at about 7 p.m. when she said a stranger physically assaulted her, according to PSU spokesman Ken Ma.

The student said the man said he had a gun, but the gun was never seen.

Public safety officers and Portland police searched the library and area but did not find the man in question.

Police are calling the man a "person of interest." He was described as a white man in his 20s, with acne scars on his face. He is of average height, wearing a black beanie, black jacket and blue jeans.

Witnesses told KGW the library was evacuated briefly while police searched the area for the man. Students were given the all-clear to return to the library at about 7:45 p.m.