[UPDATES BELOW] The campus of Virginia Tech, where a student fatally shot 32 people and wounded dozens of others in 2007, is again besieged by an armed gunman. According to the campus newspaper a police officer has been shot and killed, and there are other reports that a second person has been wounded. Students and faculty are being advised to stay indoors, and a campus bulletin obtained by the Times says the shooter was last seen traveling on foot in the direction of a recreational sports. He's described as a “white male, grey sweatpants, grey hat w/neon green brim, maroon hoodie and backpack.”

According to a local TV, the shooting may be the result of a nearby traffic stop. One report says the shooter fired at the officer who made the stop, and the officer returned fire. We'll update as more information becomes available.

Update 2:04 p.m.: Virginia Tech confirms that two people have been killed, one of whom was a Virginia Tech Police officer. School officials issued this statement:

Shortly after 12 p.m. 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. Several law enforcement agencies have responded to assist. Virginia State police has been requested to take lead in the investigation

Status of the shooter is unknown. The campus community should continue to shelter in place and visitors should not come to campus

Update 3:05 p.m.: The gunman is still at large. (School officials have announced that final exams scheduled for tomorrow have been canceled, according to the campus paper Twitter feed.) Here's video taken shortly after the shooting:

Update 4:30 p.m.:
Officials will hold a press conference soon, but law enforcement officials tell NBC News they believe the second shooting victim was the man who shot and killed the campus policeman.

Update 5:40 p.m.:
The campus alert has been lifted, and during the press conference, university official Larry Hincker said, "We're all trying to figure out what's going on. We're trying to piece it together." Officials would not confirm that the second victim was the shooter, but the weapon has been recovered. Dr. Deisinger, Dept Chief of Virginia Tech PD, said:

Earlier today the VT community lost one of its guardians... Someone witnessed a subject approach the officer and fire a weapon at an officer and then leave the scene. Virginia Tech police responded to the scene, where they found the officer had suffered a gunshot wound. We requested immediate assistance for local and state authorities. At approximately 1 p.m. an officer observed a suspicious subject in the parking lot off of Duck Pond drive [a.k.a. "the cage"]. Upon approach they found a victim dead of a gunshot wound. Since the 2nd incident there have been no further confirmed threats to the community.

And Dr. Charles Steger, President of the University, said, "As you all know, today tragedy again struck VA Tech when a police officer was killed during a routine traffic stop. Our hearts are broken again for the family of our police officer. Police officers on this campus and on every police force in the nation routinely put themselves at risk for our safety."