Law enforcement agencies and local city representatves give a news conference on Sunday, June 12, 2016, in the wake of a mass
Jacob Langston/Orlando Sentinel/TNS via Getty Images

Update (6/12, 3:00 p.m.): President Barack Obama addressed the shooting this afternoon, calling it “an act of terror and an act of hate.” Watch his entire statement here, via the White House. 

Original Story: A lone shooter opened fire on a gay nightclub in Orlando early Sunday morning, killing 50 and injuring at least 53 people, the New York Times reports. Local and federal law enforcement agencies have described the shooting as "an act of domestic terror."  

Authorities have confirmed the shooter as 29-year-old Omar Mateen, an American citizen and resident of Port St. Lucie, Florida. 

Mateen attacked Pulse, a popular LGBT nightclub in Orlando at around 2:00 a.m. Sunday, firing rounds into the ceiling and into hordes of people, officials said. The killer was armed with an assault rifle and handgun, and authorities are investigating whether or not he had explosive devices in his possession. As the gunman opened fire, the crowd nearing 300 people was sent into a panic, while attendees—some injured with gunshot wounds—poured out into the streets, notes the Times. Others fled to the venue's bathrooms, where they called for help as a hostage situation developed, authorities said. 

SWAT teams responded at approximately 5 a.m., storming the club after coordinating a series of controlled explosions to break down a wall, The Guardian reports. Orlando police chief John Mina claimed on Sunday that there were "at least 30 people that were saved during that rescue.” The gunman was killed in a gun battle with the SWAT team, authorities said. 

Orlando sheriff Jerry Demings called the incident “a domestic terror incident,” on Sunday. The FBI is currently investigating whether the suspect was linked to an outside terror organization. Speaking to the press Sunday, an FBI agent said: “At this time we’re looking into all angles," noting that Mateen may have had "leanings" toward a Jihadist ideology, The Guardian reports. 

Orlando Mayor Buddy Dyer declared a state of emergency on Sunday, and told Wesh-TV that he's "never seen anything like this, I hope no mayor ever has to see anything like this.” The number of casualties—50 dead and 53 injured as of late Sunday morning—makes the shooting at Pulse nightclub the the deadliest mass shooting in American history, according to BuzzFeed News. The shooting comes one night after singer Christina Grimmie was killed by a gunman after a concert in Orlando. Authorities say the incidents are not linked. 

Police have set up a hotline for victim's families, and for anyone who may have had a loved one at Pulse during the incident. Hotline: 407-246-4357

For more updates on the situation, follow live-blogs and reporting from The New York TimesThe Guardian, CNN and BuzzFeed News