The deadliest school shooting in US history spread shock waves though the United States Monday, reviving calls for tighter gun control and renewing the debate about campus security.
President George W. Bush led expressions of dismay saying he was "shocked and saddened" by the shooting rampage that left at least 33 dead and 15 wounded at a university in Virginia.
"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," Bush said in a brief statement.
"Today our nation grieves with those who have lost loved ones at Virginia Tech."
The House of Representatives and Senate both observed a moment of silence for what House Speaker Nancy Pelosi described as a "terrible, terrible tragedy" after a gunman killed at least 30 people before turning the gun on himself.
"This is a very dark day in Virginia history," agreed the state's Attorney General Bob McDonnell. "This senseless tragedy has just hurt us to our very soul."
The massacre at Virginia Tech University came almost eight years to the day after the shootings at Columbine High School, Colorado, in which 15 people were killed, and six months after six people including the gunman died at an Amish school in Pennsylvania.
"Since these killings, we've done nothing as a country to end gun violence in our schools and communities," said Paul Helmke, president of the Brady Campaign to Prevent Gun Violence.
"If anything, we've made it easier to access powerful weapons," he said. "It is long overdue for us to take some common-sense actions to prevent tragedies like this from continuing to occur."
The National Rifle Association expressed "deepest condolences" to the families and added: "We will not have further comment until all the facts are known."
Virginia's governor, Timothy Kaine, was cutting short a visit to Japan and said "it is difficult to comprehend senseless violence on this scale."
University president Charles Steger said they had received expressions of sympathy from around the world.
Canada's Public Security Minister Stockwell Day said "the shock and horror of this act has reverberated throughout Canada," while Liberal MP Michael Ignatieff added: "Such a senseless act leaves Canadians stunned and horrified."
In New York, British Foreign Secretary Margaret Beckett opened a speech to business leaders by saying "how horrified we are by the shooting... and how our hearts go out to those affected."
Gerard Toal, a professor at Virginia Tech, told AFP the incident would deeply affect the staff and more than 26,000 students.
"This is a profound event obviously and it's one that will shake at the core of the university," he said.
California Governor Arnold Schwarzenegger said the "horror this unprecedented carnage inflicts on our entire nation is unfathomable."
Ladd Everitt of the Coalition to Stop Gun Violence said such shootings cast a dark shadow over the entire country.
"We still live in a society where gun violence is an overriding concern," he said. "We've had a series of these high-profile, very violent shootings that have taken a lot of victims."
His organization campaigns for "sensible" gun laws, focusing on closing loopholes that allow people to get hold of weapons without background checks.
Helen Stubbs, associate director of the Higher Education Center, which helps schools tackle violence and drugs on campus, said it was difficult for campuses to have watertight security because they were often so spread out.
High schools, which in the United States often feature metal detectors at entrances, were more contained environments where security could be better monitored, she said.
