Authorities initiated lockdown on the Virginia Tech campus Thursday after three youths reported a man carrying a gun covered with a cloth.  Virginia Tech suffered a mass school shooting in 2007.  Thirty-two students were killed and 25 were wounded.   

The school's website immediately alerted students and issued the following statement on the school's website: "Person with a gun reported near Dietrick.  Stay inside. Secure doors. Emergency personnel responding. Call 911 for help."

Chief of Virginia Tech's police Wendell Flinchum said in a news conference that police were still looking for the man and that all students should remain in their rooms. 

The man was described as wearing a blue and white striped shirt, gray shorts, and brown sandals. Officers were unable to find a man consistent with the description.

Virginia Tech was criticized for not reacting quickly when gunman Seung-Hui Cho shot and killed 32 people, then himself, in April 2007.

Cho, a 23-year-old English major, frightened professors with his extremely violent writings and was ordered to see a university psychologist.  The gunman also mailed a manifesto of delusional letters, pictures, and video to NBC News.

School spokesman Larry Hincker said in a news conference that "We're in a new era. Obviously, this campus experienced something pretty terrible four years ago."

The university remains on lockdown and classes have been cancelled.  Some professors have been instructed to keep students locked in their classrooms.