President Obama has not spoken publicly today, but the White House says he will observe a moment of silence Monday on the South Lawn in honor of the shooting victims in Arizona.

“Tomorrow at 11:00 a.m. eastern standard time, 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," Obama said in a statement. "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."

The president signed a proclamation calling for flags to be flown at half-staff at the White House, all public buildings and grounds, naval stations and vessels, at U.S. embassies and military installations abroad etc., until sunset on Jan. 14.

The White House also is postponing a trip Obama was planning to take on Tuesday to Schenectady, NY., to visit a General Electric energy facility.