US President Barack Obama (C) pauses while speaking at the University of Colorado Hospital after he met with families bereaved after a gunman went on a shooting rampage at a movie theater in Aurora, Colorado July 22, 2012.  [Photo/Agencies]

AURORA, Colo - US President Barack Obama on Sunday traveled to Colorado and offered hope and comfort to victims of the gunman who killed 12 people and wounded 58 in a Denver-area movie theater.

The shooting spree early on Friday shocked the nation and dominated the news. Obama met privately with the families of victims and said he had listened to stories about those who were killed and those who risked their lives to help others.

"They assure us that out of this darkness a brighter day is going to come," Obama said at the University of Colorado Hospital in Aurora, Colorado, recounting the story of a young woman who stopped the bleeding of her wounded friend with one hand and called for help on her cell phone with the other.

After justice was done, memory would focus on the victims, not the killer, he said.

Obama said in a televised address after meeting the families that he told them that the nation was watching and shared their grief. He spoke shortly before a memorial service by the community.

"The entire country will be there in prayer and reflection today," he said.

A makeshift memorial sprang up in the town of 325,000, while across the nation on Sunday, people mourned the dead, honored those who shielded others from harm and debated whether gun control could stop such tragedies.

The gunman, identified by police as graduate school dropout James Eagan Holmes, carried an assault rifle, shotgun and handgun into a packed midnight premiere of the Batman film "Dark Knight Rises" on Friday morning.

His spray of bullets took the lives of victims ranging from a 6-year-old girl to a 51-year-old man. Many of the wounded are still in the hospital.

Iraq war veteran Christina Blache said she thought the shots were part of the show. But she was hit and a friend who was celebrating his 27th birthday died. "Who expects to be shot in a movie theater? None of us did," she told CNN.