At least 32 people were killed by a gunman who then killed himself at Virginia Tech university in the deadliest campus shooting in US history.
15 other people were injured.
US President George W Bush said tonight that schools should be places of safety and sanctuary and learning.
'When that sanctuary is violated the impact is felt in every American classroom and every American community,' he said.
The shootings took place in two separate areas of the campus and police believe a single gunman was responsible.
Police said they were investigating whether the gunman killed himself or was killed by authorities.
Most of the shootings took place at a part of the campus called Norris Hall, according to campus police chief Wendell Finchum.
All classes at the University today and tomorrow were cancelled by the 'This is a tragedy of monumental proportions,' Virginia Tech president Charles Steger told reporters.
It is the deadliest campus shooting in US history, worse than the infamous 1966 incident at the University of Texas in Austin when Charles Whitman went to top of the tower in the middle of campus and opened fire on people 27 stories below.
Whitman killed 15 people, including his mother and wife the night before, and wounded 31 others.
In April 1999 two student gunmen killed 12 other students and a teacher at Columbine High School in Littleton, Colorado, before killing themselves.
The death toll in Blacksburg is second only to a bombing in 1927 at the Consolidated School building in Bath village, near Lansing, Michigan, that killed 38 children and seven teachers.
Virginia Tech, with 28,000 students, is located in the southwest of the state, about 425km from Washington DC.
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