U.S. President Barack Obama took a break from campaigning for reelection to speak about the tragedy in the state of Colorado where a gunman burst into a packed movie theater and shot at least 12 people dead.
Obama said he was "shocked and saddened" by the mass shooting and offered condolences to family and friends of the victims, saying the people of the U.S. stand by them.
"We will take every step possible to ensure the safety of all of our people. We're going to stand by our neighbors in Colorado during this extraordinarily difficult time," Obama said.
The gunman, identified as 24-year-old James Holmes, entered the theater in the Denver suburb of Aurora during a premier showing of the new Batman movie "The Dark Knight Rises." Wearing a gas mask he threw a gas canister and opened fire on the audience. Besides those killed, several dozen people were wounded.
Alex Milano, a witness to the shooting, said police and emergency workers carrying stretchers rushed into the theater to retrieve numerous shooting victims, including children.
"A cop came walking through the front door before everyone was cleared [out] and before everything was completely under control. The cop came walking through the door with a little girl in his arms, and she wasn't moving," Milano said.
Police reportedly apprehended Eagan who was carrying a knife, a rifle, and a handgun, and was wearing a bulletproof vest. Police also went to Eagan's apartment and found it booby-trapped. The area around Eagan's flat was evacuated after demolition specialists found flammable and explosive materials in the apartment.
The FBI said there is no apparent link between Eagan and any terrorist organization.
Obama and his challenger for the presidency in elections later this year Republican Mitt Romney suspended their campaigning and called for prayer and unity.