Prime Minister Binyamin Netanyahu sent a letter expressing his condolences to US President Barack Obama on behalf of Israel on Saturday, a day after a shooting at a movie theater in the town of Aurora in Colorado, which killed 12 people.
"Israel stands with the American people as you mourn this terrible tragedy, which claimed the lives of so many people. We know the pain and loss you are experiencing," wrote Netanyahu in the letter, which also expressed condolences to the families and wished a speedy recovery to the wounded.
A gunman in a gas mask and body armor killed 12 people at a midnight premiere of the new "Batman" movie early on Friday, sparking pandemonium when he hurled a gas canister into the auditorium and opened fire on moviegoers.
Armed with an assault rifle, a shotgun and a pistol, he wounded another 59 with gunfire during a screening of "The Dark Knight Rises" at a mall in the suburb of Aurora, which turned into a chaotic scene of bleeding victims, horrified screams and pleas of "I'm hit, help me," witnesses said.
The suspect, identified by police as James Eagan Holmes, 24, also booby-trapped his Aurora apartment with sophisticated explosives, creating a hazard for law-enforcement and bomb squad officers who swarmed to the scene.
Authorities evacuated five nearby buildings, and created a perimeter of several blocks.
Arriving on the scene within 90 seconds of the first emergency calls, officers immediately took the suspect into custody in the parking lot behind the cinema, where he surrendered without a fight, Aurora Police Chief Dan Oates said.
The suspect was armed with an AR-15 assault rifle, a 12 gauge shotgun and a Glock .40 caliber handgun, Oates said. Police found an additional .40 gauge handgun in his car parked just outside the rear entrance to the cinema, Oates said.
Holmes is a University of Colorado medical school student who was in the process of dropping out of a graduate program in neurosciences, the university said in a statement.
His family issued a statement of sympathy for the victims and asked for privacy while they "process this information."
Holmes had only a speeding ticket on his criminal record and was dressed in black with a gas mask, ballistic helmet, vest, throat guard and crotch guard, Oates said.
The living room of the suspect's apartment was crisscrossed with trip wires connected to what appeared to be plastic bottles containing an unknown liquid, said Chris Henderson, Aurora's deputy fire chief. Authorities planned to detonate the suspected explosives with a robot, he said.
"The pictures are fairly disturbing. It looks very sophisticated, how it's booby-trapped. It could be a very long wait," Oates said.
Obama, Romney pull campaign ads from Colorado
The gunman appeared at the front of the theater during the movie and released a canister which let out a hissing sound before gunfire erupted, police said.
"When we got out of the theater it was just chaos. There was this one guy on all fours, crawling. There was this girl spitting up blood," witness Donovan Tate told KCNC television. "There were bullet holes in some people's backs, some people's arms. There was this one guy who was stripped down to just his boxers. It looked like he was shot in the back or something. It was crazy."
Confusion reigned as shooting broke out during an action scene in the summer blockbuster, one of the more highly anticipated films of the year. The gunman may have blended in with other moviegoers who wore costumes as heroes and villains.
"He looked like he was in the military or like he was a SWAT person so he just kind of blended in with the chaos of the crowd. People thought he was probably like a cop or something," witness Jennifer Seeger told NBC's "Today."
Chandler Brannon, 25, who had been watching the movie with his girlfriend, said that about 20 minutes into the movie he saw a smoke bomb go off and heard what sounded like fireworks. He later realized they were a rapid volley of gunshots.
"I told my girlfriend to just play dead," he told Reuters. "All I could see was a silhouette."
Obama and his Republican presidential candidate Mitt Romney, pulled their campaign ads from Colorado and dedicated their campaign events to sympathy for the victims.
"There are going to be other days for politics. This, I think, is a day for prayer and reflection," Obama told supporters at a previously scheduled campaign event in Fort Myers, Florida, which he cut short to address the shooting.
Shooting evokes memories of Columbine massacre
The shooting evoked memories of the 1999 massacre at Columbine High School in Littleton, also a Denver suburb and 17 miles (27 km) from Aurora, where two students opened fire and killed 12 students and a teacher.
Bodies of victims remained in the theater while the investigation continued with some 200 local police, 100 FBI investigators and 25 representatives of the US Bureau of Alcohol, Tobacco, Firearms and Explosives on scene, officials said.
US military personnel apparently were among the casualties but it was not immediately clear whether any were killed, the Defense Department said.
Buckley Air Force Base is the largest employer in Aurora, a city of more than 320,000 people, according to the Aurora Economic Development Council.
"Our hearts go out to those who were involved in this tragedy and to the families and friends of those involved," read a statement from Holmes' family in San Diego that was read by police there.
Security precautions taken at screenings of Batman film
In New York, police will deploy officers at screenings of "The Dark Knight Rises" throughout the city "as a precaution against copycats," Police Commissioner Raymond Kelly said in a statement.
The Paris movie premiere was canceled on Friday, event organizers said. Workmen cleared away barriers that had been set up in preparation for the premiere at a cinema on the capital's Champs Elysees avenue.
"Warner Bros. is deeply saddened to learn about this shocking incident. We extend our sincere sympathies to the families and loved ones of the victims at this tragic time," said Jessica Zacholl, a spokeswoman for Time Warner-owned Warner Bros., the studio behind the film.
The film, with a budget of $250 million, opened on 4,404 screens, the second widest release ever behind "Twilight: Eclipse," and industry analysts had said it stood a good chance of matching or beating the opening weekend box office record of $207 million set by Disney's "Avengers" in May.