Updated: 6:04 p.m.

President Barack Obama is asking the nation to observe a moment of silence at 11 a.m. EST Monday for the people killed and wounded in the shooting Saturday in Arizona.

“I call on Americans to observe a moment of silence to honor the innocent victims of the senseless tragedy in Tucson, Arizona, including those still fighting for their lives,” the president said in a statement Sunday. “It will be a time for us to come together as a nation in prayer or reflection, keeping the victims and their families closely at heart.” 
 
A gunman opened fire at a constituent event hosted by Rep. Gabrielle Giffords (D-Ariz.) in Tucson. Six people were killed, and Giffords and 13 others were wounded. The Congresswoman is in critical condition.

Obama also signed a proclamation calling for flags to be flown at half-staff.
 
A presidential trip Tuesday to Schenectady, N.Y., has been postponed, the statement said.