UPDATE: 3:26 p.m.

The death toll in an early Sunday mass shooting in an Orlando nightclub has jumped dramatically, making it the deadliest mass shooting is U.S. history.

Officials now say 50 people were killed when a Florida man in his late 20s identified as Omar Mateen opened fire in the gay club around closing time.

Rep. Alan Grayson (D-FL) said there was an “enormous amount of havoc” on the scene.

It was originally reported that the shooter killed approximately 20 people and injured dozens of others after opening fire in the nightclub.

But, Orlando Mayor Buddy Dyer said in a news conference later in the day that the death toll had risen to 50 people and 53 people were injured.

Officials said Mateen was armed with an AR-15 assault rifle and a handgun. An ATF official said in a news conference Sunday that Mateen legally purchased two guns within the last “few days.”

NBC News and CNN reported, citing anonymous law enforcement officials, that Mateen called 911 and pledged allegiance to Islamic State leader Abu Baker Baghdadi. An FBI official confirmed Sunday in the news conference that the call took place and the Islamic State was discussed, but did not disclose the contents of the conversation.

Mateen died in a shootout with SWAT members as they tried to free some 30 hostages he was holding in the club.

NBC News reported that Mateen was 29. A police officer was injured in the incident.

Mateen’s father, Mir Seddique, told NBC News that the incident “has nothing to do with religion.” He said that his son was angered a couple months ago when he saw two men kissing in Miami and thinks that it may be related to the shooting.

“We are saying we are apologizing for the whole incident. We weren’t aware of any action he is taking. We are in shock like the whole country,” Seddique said.

Seddique told NBC that Mateen was a father and a husband. He reportedly worked in security. NBC reported he had active gun licenses.

The FBI investigated Mateen twice before. The first, in 2013, an FBI official said in a news conference Sunday was launched due to “inflammatory” comments he made to co-workers. In 2014, he was investigated for potential ties to an American suicide bomber. Mateen was interviewed in both investigations and both were closed.

Florida Gov. Rick Scott (R) said it was “clearly an act of terror that should make every American angry.”