Virginia Tech police lifted a campus lockdown five hours after three children reported a man with a gun at 9:09 a.m. Thursday.

"There will continue to be a large police presence on campus today. Police have not received nor discovered additional information about a person possibly carrying a weapon beyond that reported this morning," the university said on its web site.

Classes were cancelled for the day after the lockdown was declared by the university.   

"The juveniles were interviewed ... officers confirming that their information is credible and at that point we decided to issue the alert," Virginia Tech Police Chief Wendell Flinchum said.

Police released a sketch of the gunman, a 6-feet tall man with light brown hair.  According to police, the man was wearing a blue and white striped shirt, gray shorts, and brown sandals.  Flinchum said that the man was not pointing or shooting the weapon.

Virginia Tech officials also warned students of the possible gunman through text messages and emails.   

"This campus experienced something terrible four years ago," campus spokesman Larry Hincker said in a press conference. "Strictly as an abundance of caution we are going to keep the campus under alert status and ask people to stay indoors," he added.

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 mailed a manifesto of delusional letters, pictures, and video to NBC News.

The lockdown was lifted at 2:42 p.m.