President Obama pledges to tackle gun violence
26 July 2012 Last updated at 07:30 BST
President Barack Obama has pledged to work with Congress on "violence reduction" after the Colorado shootings highlighted the issue.
Ahead of the US presidential election, Mr Obama was careful not to alienate gun owners and emphasized his support for Americans' legal right to bear arms.
However, he called for tougher checks to prevent criminals or mentally-unbalanced people from obtaining firearms.