Two people, including a police officer, have been killed in a shooting on the US’s Virginia Tech university campus, scene of America’s worst gun massacre four years ago.
The gunman fled on foot, and police - some in full combat gear - swarmed the campus in southern Virginia in a massive manhunt.
Students and faculty were ordered to stay inside university buildings and dormitories.
The campus police officer was shot dead during a routine traffic stop in what news reports said was an exchange of gunfire. A second victim was found in a nearby parking lot, Virginia Tech said in a statement.
It was the first shooting at Virginia Tech since April 2007 when a mentally deranged student killed 32 people and wounded 25 others before committing suicide on the school's rural campus in the Shenandoah Valley roughly 400km (250 miles) from Washington DC.
The massacre was the deadliest attack by a single gunman in US history.
"Everyone has been directed to stay indoors, lock all exterior doors and stay away from the windows," school spokesman Dana Cruikshank said as students' parents frantically tried to locate their children by mobile phone and social networking sites.
"Right now it's kind of scary and hectic around here that this is happening again," Matthew Spencer, a Virginia Tech freshman, told a local NBC station.
The school, formally known as Virginia Polytechnic Institute and State University, was criticised for its slow response to the 2007 incident and has since put a campus-wide alert system in place.
The campus was locked down as the search for the gunman proceeded. Final exams set to begin tomorrow for the fall semester were postponed.
Elizabeth Sullivan, a sophomore, said about 200 students were sent to the second floor of the Squires Student Center from the ground floor about an hour after the shooting.
Shortly after that, a Swat team arrived to pat down each student and check every bag in the building." "I was pretty nervous at first. I didn't really know what was going on," Sullivan told a local NBC television station.
She said most students had been keeping in touch with their families through Facebook and Twitter.
The 2007 Virginia Tech massacre renewed a chorus of calls for tougher gun control laws, particularly in the US Congress.
But these calls did not get far since Republican lawmakers have traditionally opposed gun control and Democrats, having been burned on the issue politically, did not push it.
Since taking office in January 2009, president Barack Obama has shied away from stiffer gun laws despite demands for it by members of his largley liberal base.
Reuters