50 Killed, 53 Injured at Orlando Nightclub in the US's Deadliest Mass Shooting

At least 50 people have been killed in a mass shooting at an Orlando, FL, nightclub, according to police. The attack took place on a weekly Latin dance night at a downtown gay club called Pulse and left 53 additional victims injured. Police say the shooter, identified as Omar Mateen, was killed inside the club. It has been declared the the deadliest mass shooting in US history.

Here's what we know so far:

• Mateen was a 29-year-old US citizen born in New York and living in Port St. Lucie, FL, according to NBC. While his exact motive is unknown, police are officially calling the attack a "terror incident."
• Mateen was a security guard who was armed with both an AR-15 assault rifle and a handgun.
• Police and Mateen engaged in a brief shootout around 2 a.m., and Mateen then went inside the club to take hostages.
• Hostages hid in restrooms and closets to call for help.
• Officers, including a SWAT team, stormed the club around 5 a.m., killing Mateen in the process. They used explosives to distract Mateen as they entered the club to kill him.
• One police officer was wounded in an exchange of fire, however, his Kevlar helmet saved him.
• ISIS claimed responsibility for the massacre but police say there is no direct connection between the group and the attack, reports Reuters.
• Two law enforcement officials told CNN that Mateen was being watched by the FBI and was on their radar as a possible ISIS sympathizer.
• Mayor Buddy Dyer has declared a state of emergency in Orlando.
• Governor Rick Scott declared a state of emergency in Florida. In a statement, he said, "We are a diverse state and we have wonderful people here in Florida that will respond with dignity, strength and fortitude in the days ahead."
• President Obama delivered a statement about the killing, saying, "The place where they were attacked was more than a nightclub, it was a place of solidarity and empowerment."

In the aftermath of the attack, hundreds are lining up to give blood at donation centers. However, the FDA still maintains that sexually active gay men are prohibited from donating blood within a year of sexual activity, which has proven to be a point of contention for the local LGBT community.

On the social media front, Facebook has activated its Safety Check feature to allow friends and family to check on loved ones in the Orlando area, and elected officials, news agencies, and other influencers are releasing up-to-the-minute statements on the attacks.

— Additional reporting by Kelsey Garcia and Mandy Harris