The nation observes a moment of silence , and church bells ring in many states . Comment: Observances mark a week since shooting that killed 20 children , 7 women and gunman .
The nation observes a moment of silence , and church bells ring in many states . President , first lady are `` holding you and your families in our hearts , '' Michelle Obama writes . Observances mark a week since shooting that killed 20 children , 7 women and gunman .