8 December 2011 Last updated at 20:13 GMT
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Mark Owczarski, a spokesman for the university: ”We are asking the campus community to stay indoors”
Virginia Tech, site of America’s worst school shooting four years ago, says a police officer and another person have been shot dead on campus.
It said the gunfire began during a routine traffic stop on campus by a Virginia Tech police officer.
The Blacksburg site is on lockdown with staff and students advised to stay indoors.
Police have swarmed the campus looking for the suspect, a white male, who escaped on foot.
Virginia Tech said on its website: “Shortly after noon today, a Virginia Tech police officer stopped a vehicle on campus during a routine traffic stop in the Coliseum parking lot near McComas Hall.
“During the traffic stop, the officer was shot and killed. There were witnesses to this shooting.
“Witnesses reported to police the shooter fled on foot heading toward the Cage, a parking lot near Duck Pond Drive. At that parking lot, a second person was found. That person is also deceased.”
The suspect was said to be wearing grey tracksuit bottoms, a grey hat with neon green brim, maroon hoodie and backpack.
Harry White, 20, a physics undergraduate, told the Associated Press news agency in a phone interview that he had been getting some lunch on campus when he received the text message alert about the shooting.
He said he initially did not take it too seriously, remembering that the campus had been placed on lockdown in August amid a report of a gunman, which turned out to be a false alarm.
“I decided to just check to see how serious it was,” he said. “I saw it was actually someone shooting someone, not something false, something that looks like a gun.”
The incident came on the same day as Virginia Tech appealed against a $55,000 (£35,200) fine imposed by the US Education Department for not reacting quickly enough to the April 2007 massacre.
Thirty-two people died when a 23-year-old South Korean, Seung-Hui Cho, went on a gun rampage before turning the weapon on himself.
The university, which has about 30,000 students, implemented a highly advanced security alert system after the tragedy.
It was put to the test in 2008, when an exploding nail gun cartridge was mistaken for gunfire.
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