shootHuffington Post – In what police are calling the worst shooting in American history, a gunman killed 50 people and injured at least 53 when he opened fire at a gay nightclub in Orlando, Florida.

Authorities say Omar Mateen stormed the downtown Pulse nightclub around 2 a.m. Sunday before opening fire and taking dozens of people hostage.

“Our SWAT officers exchanged gunfire with the suspect. The suspect is dead,” Orlando Police Chief John Mina said at a press conference. “He appeared to be carrying a rifle, an assault-type rifle and a handgun and had some type of device on him.”

Mateen, of Port St. Lucie, Florida, “was organized and well-prepared,” the FBI said, according to ABC News.

FBI agent Ron Hopper said the suspect may have leanings toward extreme Islamic ideologies, the Orlando Sentinel reported.

Around 5 a.m., authorities decided to attempt to rescue the hostages, leading to a gunfire exchange that ended in the suspect’s death, Mina said.

“We are investigating this from all points of perspective as an act of terrorism,” said Special Agent Danny Banks, who’s in charge of the Florida Department of Law Enforcement. “Any time we have potentially dozens of victims in any of our communities then I think we can qualify that as terrorism activity. Whether that is domestic terrorism activity or an international one is certainly something that we will get to the bottom of.”

Witnesses recalled hearing a barrage of gunfire at the start of the violence. The dance club urged patrons to “get out” and “keep running” in a post on its Facebook page.

Javer Antonetti, 53, told the Sentinel that he was near the back of the dance club when he heard the gunfire.

“There were so many [shots], at least 40,” he said. “I saw two guys and it was constant, like ‘pow, pow, pow.’”

Police said they had carried out a “controlled explosion” at the club hours after the shooting broke out, but did not say why that was done. They described the scene as a “fluid situation.”

Video posted online showed a large number of police and emergency vehicles outside the nightclub. Bomb-sniffing dogs were also on the scene, CNN reported.

It was the second deadly shooting at an Orlando night spot in as many nights. Late Friday, a man thought to be a troubled fan fatally shot Christina Grimmie, a rising singing star and a former contestant on “The Voice,” while she was signing autographs after a concert in the Florida city.

There was an outpouring of support from the community as they took in the morning’s horrors.

Nadine Smith, CEO of Equality Florida, which advocates gay and lesbian rights statewide, said they are holding off judgment until more information is released.

“We have received a steady stream of emails and messages from those seeking to help or to make sense of the senseless. We make no assumptions on motive. We will await the details in tears of sadness and anger. We stand in solidarity and keep our thoughts on all whose lives have been lost or altered forever in this tragedy,” she said in a statement.

Imam Muhammad Musri, who leads the Islamic Society of Central Florida, asked for prayers for the families of the victims.

No one could have predicted this, no one could have prepared for it,” he said on Sunday. “This could have happened anywhere. It’s like lightning … Whatever faith you follow please pray for the victims and their families in this hour, in this Sunday morning.”