The 22-year-old accused of trying to assassinate a U.S. congresswoman and killing six others has made his first appearance in court.
Jared Loughner was ordered held without bail at the hearing in Phoenix in the southwestern state of Arizona,
Loughner could face the death penalty if found guilty.
Earlier, Americans observed a moment of silence for the six killed and 13 wounded in the January 8 shootings outside an Arizona supermarket.
Outside the White House, President Barack Obama and first lady Michelle Obama stood side by side, heads bowed and eyes closed.
Obama called for the country to come together in prayer or reflection for those killed and those fighting to recover.
"In the coming days, we're going to have a lot of time to reflect. Right now, the main thing we're doing is to offer our thoughts and prayers to those who've been impacted, [and] making sure that we're joining together and pulling together as a country," Obama said. "And as president of the United States, but also as a father, obviously I'm spending a lot of time just thinking about the families and reaching out to them."
U.S. Representative Gabrielle Giffords, meanwhile, remains in critical condition with a bullet wound to the head.
The shootings have dominated news in the United States, prompting outrage and sparking debate over gun control and whether heated political rhetoric fueled the incident.
compiled from agency reports