Congressional staff members walk on Capitol Hill in Washington, D.C. on Monday after observing a moment of silence for congresswoman Gabrielle Giffords, who was shot Saturday in a Tucson rampage that left six people dead.

The night before she was wounded in a shooting that killed six people Saturday, Arizona congresswoman Gabrielle Giffords sent an email to a friend in Kentucky discussing how to promote moderation.

The message — obtained by The Associated Press — was sent to Trey Grayson, the outgoing Republican secretary of state for Kentucky, congratulating him on a new position he accepted at Harvard University.

Giffords, a Democrat, said that after he was settled in his new position, she would love to talk to him about what they could do to promote centrism.

"We need to figure out how to tone our rhetoric and partisanship down," she wrote.

The next day, Giffords was shot in the head at a political meet-and-greet in Tucson, Ariz. Six people — including a federal judge — died in the shooting and Giffords remained in critical condition Monday. Jared Lee Loughner, 22, has been charged 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.

Saturday's shooting has U.S. politicians of all stripes calling for a toning down of the intense rhetoric some feel may have been a factor in the attack.

In the hours after the shooting, a disturbing array of information emerged about Loughner, a self-described Adolf Hitler fan with a loathing of government. Revelations that he was a "political radical" angry at government resulted in almost immediate political ramifications.

Leading congressional Republicans said they would postpone plans to vote on repealing President Barack Obama's health-care legislation this week in Congress. The website of Sarah Palin's action committee also swiftly removed a map of the U.S. that featured Giffords's congressional district, along with several others, placed under crosshairs.

Obama calls for calm

Reporting from Washington, Susan Bonner of CBC News said that rightly or wrongly a lot of focus in the U.S. has turned to Palin's role in inflaming the political debate in the United States. Obama has called for calm.

"The president is trying very hard to stay above this political debate that's happening as part of the fallout from the weekend shooting," Bonner reported. "The president is asking the nation to remember the victims, saying that Americans are still grieving."

Still, much of the criticism in the aftermath of the shooting has turned to Palin, particularly her penchant for injecting gun imagery into her political messaging. A favoured Palin saying is: "Don't retreat, reload."

Giffords personally complained last year about the crosshairs map in eerily prescient remarks.

"The way that she has it depicted has the crosshairs of a gunsight over our district. When people do that, they have got to realize there are consequences to that," Giffords said in March.

On Sunday, in the first detailed comments from the Palin camp since the shooting, an aide insisted the crosshairs map was never meant to encourage violence.

"We never, ever, ever intended it to be gunsights," Rebecca Mansour told talk radio host Tammy Bruce. "It was simply crosshairs like you'd see on maps ... it never occurred to us that anybody would consider it violent," she added, branding any attempts to politicize the tragedy as "repulsive."

Nonetheless, online petitions were cropping up online Monday calling for Palin, a likely Republican presidential contender in 2012, to face federal charges for "inciting violence" against Giffords and other Democrats.

Indeed, Giffords's support of so-called Obamacare made her a popular target of Palin and Tea Party members last year. In March, after the health-care legislation passed, her Arizona office was vandalized.

Dick Durbin, a Democrat who's the Senate majority whip, said Sunday it's time for politicians of all stripes to reflect.

"We live in a world of violent images and violent words, but those of us in public life ... should be thoughtful in response to this," he said on CNN.

"We owe it to our own in both political parties to at least have the good sense and common decency ... to say, 'Wait a minute, that just goes too far,' whether it's from the right or the left."

Lamar Alexander, a Republican senator from Tennessee, said his party will ease up in the days to come.

"Obviously it's going to affect our agenda. We need to stop, pause and reflect," he told CNN. "But after that, it's back to business."

With files from The Canadian Press