Obama Leads Moment of Silence for Tucson Victims

Updated at 11:32 a.m. ET

WASHINGTON - A somber President Barack Obama led a moment of silence on Monday for a nation stunned by an attempted assassination against an Arizona congresswoman that left her seriously wounded, several other injured and six people dead.

On a frigid Washington morning, the president and first lady Michelle Obama walked out of the White House to the sounding of a bell at 11 a.m. Both wearing overcoats, they stood next to each other on the South Lawn, each with their hands clasped, heads bowed and eyes closed.

After a minute of silence, they walked inside, the president's hand on the first lady's back.

Special Section: Tragedy in Tucson

The moment was marked on the steps of the U.S. Capitol and around the nation on the direction of the president, who called for the country to come together in prayer or reflection for those killed and those fighting to recover.

In total, 19 people were shot in the shooting rampage in Tuscon, Ariz. on Saturday. Democratic Rep. Gabrielle Giffords was shot point-blank in the head, and she remains in intensive care. Among the six people killed were Arizona's chief federal judge, a 9-year-old girl interested in government, and one of Giffords' aides. Giffords' orbiting brother-in-law, astronaut Scott Kelly, called for a moment of silence aboard the International Space Station and at all the flight control centers around the world.

"We have a unique vantage point here aboard the International Space Station. As I look out the window, I see a very beautiful planet that seems very inviting and peaceful. Unfortunately, it is not," Kelly radioed to Mission Control in Houston. "These days, we are constantly reminded of the unspeakable acts of violence and damage we can inflict upon one another, not just with our actions, but also with our irresponsible words. We're better than this. We must do better."

Kelly, the space station commander, described Giffords as "a caring and dedicated public servant."

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Dr. Michael Lemole, one of the two surgeons to operate on Giffords Saturday, told CBS News that the congresswoman was "holding her own."

Prosecutors charged 22-year-old Jared Loughner with one count of attempted assassination of a member of Congress, two counts of killing an employee of the federal government and two counts of attempting to kill a federal employee. More charges are expected.

So far, Loughner hasn't cooperated with authorities and has offered no motivation for the attack, reports CBS News correspondent Bob Orr. He is due in court later Monday but isn't expected to say much, having invoked his 5th Amendment rights.

House Speaker John Boehner told lawmakers in a conference call Sunday to "pull together as an institution."

"What is critical is that we stand together at this dark time as one body," he said. "We need to rally around our wounded colleague, the families of the fallen and the people of Arizona's 8th District. And, frankly, we need to rally around each other."

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Giffords, a Democrat, represents Arizona's 8th District.

House business this week, including a contentious vote scheduled for Wednesday to repeal Mr. Obama's new health care law, has been postponed to focus on any necessary actions in the shooting aftermath.

Connecticut Rep. John Larson, who heads the House Democratic Caucus, said Sunday that lawmakers will continue to have open sessions with their constituents, although they are likely to take more precautions.

The chief law enforcement official in the House, Sergeant-at-Arms Bill Livingood, is holding a conference call Monday with House members to discuss security.