DURHAM, N.H. — The University of New Hampshire police department is investigating a report that a student was sexually assaulted in her dorm room by a stranger.

University spokeswoman Erika Mantz said the student reported being assaulted around 3:30 a.m. Sunday in Stoke Hall. The victim did not know the assailant, whom she described as dark skinned with dark hair and wearing a dark shirt.

Authorities have not said whether the victim was injured. No arrests have been made, and UNH police released no further details today.

The campus community was notified of the assault through an emergency text message as required under the federal Clery Act, a campus crime-reporting law. According to the most recent statistics collected under that law, there were 48 reports of forcible sexual assault at campuses across the state in 2010, including 12 at the University of New Hampshire, the state’s largest university with approximately 15,000 students. That was up from eight in 2008 and 10 in 2009.

Dartmouth College, with about 6,000 students, also had 12 reports of forcible sexual assault in 2010, compared with 22 in 2008 and 10 in 2009.

A year ago, Vice President Joe Biden chose the University of New Hampshire as the backdrop for a new initiative aimed at reminding colleges and universities of their responsibility to prevent sexual violence. UNH was chosen for the announcement because of its highly regarded violence prevention efforts and victim support services, including 24-hour victim assistance.

Nearly 20 percent of female college students will be victims of attempted or actual sexual assault, as will about 6 percent of undergraduate men, according to data provided by the Education Department.