The deadliest student shooting in American history has left at least 33 people dead and around 10 injured as a gunman rampaged through a university.

The violence brought chaos to the campus in Virginia as the killer opened fire in a hall of residence and a classroom.

American President George Bush was said to be "horrified" by the shootings at Virginia Tech university in Blacksburg which began just after noon (BST).

The gunman has been killed but it is not known if he was a student or whether he was shot by police or took his own life.

The university’s president Charles Steger said: "Today the university was struck with a tragedy that we consider of monumental proportions. The university is shocked and indeed horrified."

Some of the victims were students, with one killed in a dormitory and the others shot in a classroom, said Virginia Tech police chief WR Flinchum.

Student Matt Maroney told Sky News that 43 people had been shot, he added that students had thrown desks at a door and a teacher was shot in the arm.

He said: "He had an ungodly amount of ammo on him. He was just dressed in a vest filled with clips and started firing away at classrooms."

Asked why someone could have committed an act like this, he said: "Our school has been closed down for severe bomb threats twice in the last week-and-a-half."

He added that some students became "really stressed out" around exam time and said: "I don’t know what would drive a kid to shoot 43 people."

Asked about security, he claimed there was nothing preventing someone from bringing "even rocket launchers" on campus.

Before today, the deadliest campus shooting in US history took place in 1966 at the University of Texas, where Charles Whitman climbed to the 28th-floor observation deck of a clock tower and opened fire.

He killed 16 people before he was gunned down by police. In the Columbine High School bloodbath near Littleton, Colorado, in 1999, two teenagers killed 12 fellow students and a teacher before taking their own lives.

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