A student from South Korea was identified on Tuesday as the gunman who killed 32 people at Virginia Tech university in the deadliest shooting rampage in modern U.S. history.
Here are some key facts on guns and gun ownership in the United States and worldwide:
* An estimated 34 percent of the citizens in the United States own firearms, and there are thought to be more than 200 million firearms in private hands.
* Private gun ownership is generally not subject to either licensing or registration. The private resale of guns is largely unregulated in the United States.
* The Second Amendment to the U.S. Constitution says "A well regulated militia, being necessary to the security of a free State, the right of the people to keep and bear arms, shall not be infringed." The National Rifle Association says this guarantees a citizen's right to keep and bear arms for personal defense.
* From 1993 to 2000, the United States was the leading supplier of conventional arms to the developing world. In 1999, more than 4 million firearms were manufactured in the United States for domestic sale or export.
* More than 300 U.S. companies produce arms and/or ammunition.
* There are 640 million guns in the world, and another 8 million new guns are manufactured annually by more than 1,200 companies in 92 countries. Ten billion to 14 billion units of ammunition are manufactured every year.
Sources: Reuters; National Rifle Association / www.nra.org; International Action Network on Small Arms/ www.iansa.org