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Virginia Tech on lockdown after reports of gunman on campus

Virginia Tech University, located in Blacksburg, Virginia Virginia Tech

(CBS/AP) BLACKSBURG, Va. - The campus of Virginia Tech was locked down Thursday when three children attending a summer camp said they saw a man holding what looked like a gun - an unsettling report on the campus where a 2007 massacre left 33 people dead.

The university issued an alert on its website at 9:37 a.m. Thursday telling students and employees to stay inside and lock their doors.

The children said they saw the man walking fast toward the volleyball courts, carrying what might have been a handgun covered by some type of cloth. Police swarmed the area but said they could not find a gunman matching their description. The university said on its website that no one else has reported a person with a gun or anything suspicious.

An alert on the school's website said the gunman was reported near Dietrick Hall, a three-story dining facility steps away from the dorm where the first shootings took place in the 2007 rampage.

On Thursday, officials said they were looking for a 6-foot-tall white man with light brown hair. Officials said the person was wearing a blue and white striped shirt, gray shorts and brown sandals. He was described as clean shaven, according to the university's website.

Police from Virginia Tech, Blacksburg and Christiansburg searched for the man along with Virginia State Police and Montgomery County sheriff's deputies. FBI spokeswoman Dee Rybiski said agents also were on their way to assist.