In the midst of LGBTQ Pride celebrations happening across the United States, a man who’d pledged allegiance to ISIS gunned down 49 people and wounded at least 53 more early Sunday morning at a gay nightclub in Orlando, making it the deadliest mass shooting in United States history.

The lone gunman, who lived in of Fort Pierce, Florida, was responsible for the attack that started shortly before 2:00 am.

The 29-year-old gunman carried an semi-automatic rifle and pistol into the packed Pulse Club unleashing shots on hundreds inside. The gunman took the club hostage for several hours shortly after engaging in a gun battle with police. More than a dozen Orlando police officers stormed into the club killing the gunman. One officer was injured during the attack when a bullet hit his Kevlar helmet causing an eye injury, with the helmet saving the officer’s life.

The FBI is still investigating the matter and are spearheading efforts to find what motivated the gunman, who was born in New York to Afghan parents. The gunman worked for the security firm G4S since 2014 and had purchased the two weapons he used just days before the attacks. FBI assistant Special Agent Ronald Hopper said that the gunman was interviewed by the FBI in 2013 after he made “inflammatory” comments to co-workers and again in 2014 after he expressed sympathy for a suicide bomber in Syria.

"At this time we're looking at all angles right now," an FBI official said. "We do have suggestions that the individual may have leanings towards that, that particular ideology. But right now we can’t say definitively, so we’re still running everything around.”

While no motive has officially been confirmed, President Obama released a statement to the nation from the White House. “Although it’s still early in the investigation. We know enough to say this is an act of terror and act of hate,” President Obama said. “This is an especially heartbreaking day for our friends who are lesbian, gay, bisexual and transgender.”

The city of Orlando has seen an enormous amount of support nationwide and Orlando officials are urging those who can help to donate blood for the recovering victims.

While officials have urged residents to come forward to donate blood, federal law prohibits any man who has had sex with another man in the past year causing an uproar within the LGBTQ community. The policy dates back to 1983, near the start of the AIDS epidemic and hasn’t changed since, meaning men who are married or in a monogamous relationship are still prohibited from donating.

The support is still coming in regardless of the policy with residents lining up to donate blood to the victims who are still recovering. Of the 49 (once 50 but now exluding the gunman per the FBI) victims who died from the shooting, 39 were killed at the club and 11 people died at hospitals while the surviving victims are recovering throughout various hospitals in the area.

“We have spent the morning operating on a number of victims,” Dr. Michael Cheatham of the Orlando Regional Medical Center told reporters. “We continue to operate on them.”