WATCH LIVE: Coverage of mass shooting in Orlando

<p>Fifty people are now confirmed dead and 53 injured after a shooting in an Orlando nightclub early Sunday morning, making it the deadliest mass shooting in American history.&nbsp;</p><p>The shooting, which police have called&nbsp;<a href="http://www.newsy.com/videos/police-say-mass-shooting-at-an-orlando-nightclub-was-terrorism/" target="_blank">an act of terrorism</a>, happened shortly after 2 a.m. Eastern time Sunday at&nbsp;<a href="http://www.pulseorlandoclub.com/" target="_blank">Pulse Orlando</a>, a gay nightclub.</p><p>A police officer working at the nightclub and two other officers nearby initially responded to the scene, which turned into a hostage situation.</p><p>A few hours later, police rescued 30 hostages and exchanged gunfire with the shooter, killing him. The gunman was armed with a handgun, an assault rifle, additional rounds and an unidentified device. After the standoff, police worked for hours to sweep the building and the suspect&#39;s car for possible devices.</p><p>The FBI has identified the shooter but hasn&#39;t released his name pending notification of family.&nbsp;</p><p>Ron Hopper, assistant special agent in charge of the FBI&#39;s Orlando office, said, &quot;If anyone out there attended this nightclub and then left before the shooting happened, I would urge you to still call in and come and talk to our investigators because you don&#39;t know exactly what you may of&nbsp;&nbsp;may not have seen.&quot;</p><p>A doctor at nearby Orlando Regional Medical Center said extra trauma surgeons came in to operate on the victims, many of whom he described as &quot;critically ill.&quot;</p><p>Orlando Mayor Buddy Dyer has declared a state of emergency in the city.</p><p><i>This video includes clips from&nbsp;</i><a href="http://www.clickorlando.com/news/several-injured-in-shooting-at-orlando-nightclub" target="_blank"><i>WKMG</i></a><i>,&nbsp;</i><a href="http://www.fox35orlando.com/news/local-news/157861372-story" target="_blank"><i>WOFL</i></a><i>,&nbsp;</i><a href="http://www.wftv.com/news/local/orlando-nightclub-shooter-identified-as-omar-s-mateen-of-port-st-lucie-fl/338280505" target="_blank"><i>WFTV</i></a><i>,&nbsp;</i><a href="http://www.cnn.com/2016/06/12/us/orlando-nightclub-shooting/index.html" target="_blank"><i>CNN</i></a><i>&nbsp;and&nbsp;</i><i><a href="http://www.orlandosentinel.com/news/breaking-news/os-orlando-shooting-pulse-nightclub-story.html" target="_blank">Orlando Sentinel</a></i><i>&nbsp;and images from&nbsp;</i><a href="https://twitter.com/OrlandoPolice/status/741902485070045184" target="_blank"><i>Twitter / @OrlandoPolice</i></a><i>&nbsp;and Getty Images.&nbsp;</i></p><hr><b>Trending stories at <a href="http://www.newsy.com">Newsy.com</a></b><ul class="inline-related-links"><li><a href="http://www.newsy.com/videos/egg-producers-pledge-to-stop-grinding-up-male-chicks/">Egg Producers Pledge To Stop Grinding Up Male Chicks</a></li><li><a href="http://www.newsy.com/videos/christina-grimmie-s-killer-might-ve-gone-to-concert-just-to-shoot-her/">Christina Grimmie&#039;s Killer Might&#039;ve Gone To Concert Just To Shoot Her</a></li><li><a href="http://www.newsy.com/videos/police-say-mass-shooting-at-an-orlando-nightclub-was-terrorism/">Police Say Mass Shooting At An Orlando Nightclub Was Terrorism</a></li></ul>