Two males assaulted a woman on the Harvard University campus early Monday, Harvard police said. The woman, a Harvard undergraduate, was crossing the courtyard of Quincy House, one of 12 residential houses for Harvard upperclassmen, at about 1:35 a.m. when the two grabbed her and attempted to pull her toward a building, campus police said in a community advisory released Monday. The woman struggled and was able to free herself without injury. She fled the courtyard and entered another nearby residential building, the campus police said. Harvard police were unable to locate the suspects but are continuing to investigate and have increased the number of uniformed officers around Quincy House.Jeremy C. Fox can be reached at email@example.com. Follow him on Twitter @jeremycfox.