50 dead in Orlando nightclub terrorism attack, state of emergency declared (Los Angeles Times/Orlando Sentinel)

A lone gunman armed with a pistol and an assault rifle killed 50 people and injured 53 more at a gay Orlando nightclub early Sunday morning in the deadliest mass shooting in American history.

The man, whom officials have identified as 29-year-old Omar Mateen of Port St. Lucie, was killed after a shootout with Orlando police.

U.S. investigators are operating under a theory that the Orlando nightclub mass shooting was inspired by Islamic State, the top Democrat on the House Intelligence Committee said Sunday.


The similarities between the November attack on the Bataclan nightclub in Paris and that the shooter who appeared to target a gay dance club during the Muslim month of Ramadan "indicates an ISIS-inspired act of terrorism," Rep. Adam Schiff, D-Burbank, said in a statement.


Intelligence officers are combing through terrorism databases to see if there are any known links between alleged shooter and a terrorist group, Schiff said.


There haven't been signs so far that Islamic State leaders helped orchestrate the plot, he said. "Whether this attack was ISIS-directed remains to be determined," he said.


Christopher Hansen, who was inside the Pulse nightclub during the attack, said he dropped to the floor when he heard about 40 gunshots. People ran from the bar as police officers screamed for everyone to leave. 


"I just fell down and crawled out," said Hansen, 23.


"I helped someone who was on the ground. I wasn't sure if he was dead or alive," he said. 


As people fled the club, Pulse Orlando posted a note to its own page that said, "Everyone get out of pulse and keep running." 


Police Chief John Mina said Mateen fired the first shot about 2:02 a.m. at an Orlando police officer and then ran into the club, which held more than 200 people. Details about exactly what happened inside the club were unclear, but police  handled it as a hostage situation.


By 5 a.m., the police department's SWAT team opened fire. They distracted Mateen with an explosive device and plowed into the building with a vehicle. When officers went inside, they discovered 50 dead, including Mateen, and 53 injured.


Mina said nine officers were involved in the shooting, and one sustained an injury to his eye and was saved by his helmet.


Mina credited his officers with rescuing 30 hostages from Pulse Orlando on 1912 S. Orange Ave., which is just south of downtown Orlando and near Orlando Regional Medical Center. 


Orlando Mayor Buddy Dyer declared the city in "a state of emergency" and Gov. Rick Scott, who was at the scene, extended it to all of Orange County.


"Tonight our community witnessed or experienced a very horrific crime," Dyer said.


In an attempt to shift family members away from ORMC, where many of the injured were taken, authorities set up an information center at a nearby hotel, Hampton Inn at 43 Columbia Street and urged relatives to call 407-246-4357.


U.S. Rep. Alan Grayson, D-Orlando, called the attack a "hate crime" because the shooting happened at a gay club.


"It's no coincidence the attack took place where it did and when it did," he said.


Authorities said there is no indication of impending attacks in Florida or across the nation. The Federal Bureau of Investigation is leading the investigation. 


Mina said the situation is not related to a separate shooting Friday inside The Plaza Live theater in Orlando, where a man opened fire, killing former NBC's "The Voice" contestant Christina Grimmie and himself.


'I saw fire coming out of his gun'


It was Latin night at the club. 


Mina said some people trapped inside the club hid in the bathrooms and called 911.


Rosie Feba was there with her girlfriend for the first time. 


"She told me someone was shooting. Everyone was getting on the floor," Feba said. "I told her I didn't think it was real, I thought it was just part of the music, until I saw fire coming out of his gun."


Feba and her girlfriend ran out of the club. On the way out, they saw a man who had been shot. 


Feba grabbed him. Others around her called 911. Some of the man's blood stained the sleeve of her striped T-shirt. 


Both Feba and her girlfriend were unharmed, but shaken. They waited in a CVS parking lot for more information.


Victims experiencing emotional trauma related to the shooting can dial 2-1-1 for support, said Ashley Blasewitz of the Heart of Florida United Way.


Looking for family 


Many of the victims were taken to ORMC, where family members gathered, hoping to get information.


Florida Hospital wouldn't comment on whether it was treating any of the injured, but said they can check on names for families.


Mina called the mass shooting “absolutely terrible. … one of the worst tragedies we’ve seen.”


He said the immediate priority is to identify the dead and injured and notify their next of kin, something that he said would require people to be patient.


“Unfortunately this tragedy and the amount of bodies that are in there, the amount of victims, is going to take some time,” Mina said.


Carlos Muniz went to OPD headquarters after the shooting to give an interview. 


"It was massacre, basically," said Muniz, who was in the club at the time of the shooting.  "And one of our friends is missing."


Muniz initially thought the shots were part of the music. 


Meanwhile, authorities scoured the area for explosive devices, using robotic devices and K-9s. In addition to carrying the weapons, Mina said Mateen was possibly wearing an explosive "device."


Imam Muhammad Musri, president of the Islamic Society of Central Florida, urged people to pray on what he called “a heart-breaking morning.”


“It’s a horrible tragedy. We are mourning,  We are sad. We are heartbroken,” he said.


A mass shooting, he added, “is the worst nightmare, and we are sorry to know that it happened to us.”


U.S. Sen. Bill Nelson said Senate intelligence committee staff “do believe there is some connection to ISIS.”


“There appears to be some connection to Islamic radicalism,” he said at a news conference at the command center in Orlando.