UPDATE 8:04 a.m. PST: President Obama and his wife Michelle led the moment of silence fromjust outside the South Portico entrance of the White House. House Speaker Boehner and Minority Leader Pelosi stood together on the Capitol steps. Groups across the country stopped for approximately a minute to honor the dead and wounded.

President Obama speaking on the phone with Arizona Gov. Jan Brewer. (White House photo by Pete Souza)

The moment of silence is scheduled for 11:00 a.m. EST on Jan. 10. Flags are to be flown at half-staff at all public buildings and grounds, military and naval posts, and naval vessels until sunset Jan. 14.

On Saturday, Jared Lee Loughner opened fire at a public meeting in Tucson, Arizona, killing six people and wounding 14 others. Loughner targeted Rep. Gabrielle Giffords (D-Ariz.), who is in critical condition after receiving a gunshot wound to the head.

Obama spoke about the shootings Saturday:

It’s not surprising that today [Saturday] Gabby was doing what she always does -- listening to the hopes and concerns of her neighbors.  That is the essence of what our democracy is all about.  That is why this is more than a tragedy for those involved.  It is a tragedy for Arizona and a tragedy for our entire country.

What Americans do at times of tragedy is to come together and support each other.  So at this time I ask all Americans to join me and Michelle in keeping all the victims and their families, including Gabby, in our thoughts and prayers.  Those who have been injured, we are rooting for them.  And I know Gabby is as tough as they come, and I am hopeful that she’s going to pull through.

Doctors are "cautiously optimistic" about Giffords recovery, saying that she is responding to simple commands. But they say it's too soon to make any predictions.

Loughner has been charged with five felony counts from the rampage, and investigators are looking into his political ties.