Biden: US has 'moral obligation' to act on gun violence


"We have a moral obligation to do everything in our power to diminish the prospect that something like this could happen again." —VP Biden

Watch live: Obama unveils gun control proposals


Obama assault weapon ban call

President Barack Obama has called for a ban on military-style assault weapons and a ten-round limit on magazines as he launched the most sweeping effort to curb American gun violence in nearly two decades.