Obama Faces Calls for Action After Connecticut Shootings

Mass killings, like Friday's schoolhouse slaughter in Connecticut, have become a troubling and recurring fact of life in the United States.

Other recent mass shootings include:

*  August 2012:  An Army veteran kills five men and a woman at a Sikh temple in Wisconsin.

*  July 2012:  A  student opens fire at a midnight showing of the latest Batman movie at a Colorado theater, killing 12.

*  January 2011: U.S. Representative Gabrielle Giffords and 18 other people are shot outside a supermarket in Arizona.

*  November 2009:  An Army psychiatrist kills 13 soldiers and civilians on the Fort Hood Army base in Texas.

*  April 2007:  A students kills 32 people on the campus of a large university, Virginia Tech.

*  April 1999: Two students at a Colorado high school kill 12 classmates and a teacher.

The Mother Jones magazine says that since 1982, there have been at least 61 mass murders in the U.S., which U.S. authorities define as an assault in which a gunman kills four or more people, typically in a single location.