U.S. President Barack Obama on Sunday left Washington for Aurora, Colorado, to meet with families of the victims of the deadly shooting that killed 12 people Friday.

Obama left Washington one day earlier than previously planned for a three-day campaign swing into the west of the country.

Obama left Washington one day earlier than previously planned for a three-day campaign swing into the west of the country. He will also meet with families of the shooting victims and local officials, before flying to San Francisco for the night.

The president will resume campaigning on Monday, after he and Republican presidential candidate Mitt Romney both called off campaign events on Friday, as the country dealt with the aftermath of the shooting.

Obama has called the tragedy a "heinous crime" that was "senseless" and "beyond reason". He pledged to seek justice while ordering that U.S. flags be flown at half-mast for six days.

Police has taken the suspect, identified as James Holmes, 24, into custody and defused all dangers in his booby-trapped apartment. Authorities say evidence indicates months of plotting, but the motives are yet to be determined.