Florida nightclub mass shooting death toll rises

A gunman killed 50 people and injured 53 in a massacre at a gay nightclub in Orlando, Florida, on Sunday.

Orlando police officers seen outside of Pulse nightclub after a fatal shooting and hostage situation on June 12, 2016 in Orlando, Florida. The suspect was shot and killed by police after 20 people died and 42 were injured. Picture: AFP.

JOHANNESBURG/ORLANDO - US police have confirmed the death toll at US gay nightclub, Pulse in Florida Orlando, has risen to 50.

The gunman is among the 50 deceased.

An additional 53 people have been injured in the massacre.

The shooter was identified as Omar S. Mateen, a man that a senior FBI official said might have had leanings towards Islamic State militants.

Officials cautioned that the Islamist tie required further investigation.

The death toll given by Orlando Mayor Buddy Dyer, made the attack the deadliest mass shooting in US history, eclipsing the 2007 massacre at Virginia Tech University, which left 32 dead.

Orlando police's John Mina says this is the worst shooting in the history of US.

"We'll determine officially whether it's a hate crime, terrorism or a violence crime once we have all the facts as we are in the very early stages."

He says authorities still need to identify the bodies and inform the next of kin.

"It's definitely a tragedy not only for the city but for the entire nation. It can happen anywhere in the United States of America and what we need to do is to continue to be vigilant and call if you see something."

A police officer working as a security guard inside the nightclub, which has operated in downtown Orlando since 2004, exchanged fire with the suspect at about 2am, police officials said.

A hostage situation quickly developed, and three hours later a squad of officers stormed the club and shot dead the gunman. It was unclear when the gunman shot the victims.

"Do we consider this an act of terrorism? Absolutely, we are investigating this from all parties' perspective as an act of terrorism," said Danny Banks, special agent in charge of the Florida Department of Law Enforcement. "Whether that is domestic terrorist activity or an international one that is something we will certainly get to the bottom of."

Additional reporting by Reuters.