US President Barack Obama on Sunday called the mass shooting at a gay nightclub in Florida, in which at least 50 people were killed and 53 others injured when a "lone wolf" gunman opened fire early on Sunday, an "act of terror" and "act of hate".
"Although it's still early in the investigation, we know enough to say that this was an act of terror and an act of hate," Xinhua quoted Obama as saying.
President Obama had ordered US flags at half-staff.
Obama's statement on Sunday marked at least the 20th time he had addressed the nation on the topic of mass shooting during his presidency.
Calling the Florida shooting spree "the most deadly shooting in American history," Obama again reminded the country of the sober reality that "how easy it is for someone to get their hands on a weapon" that could launch mass killings.
Following the 2012 school mass shootings in Newtown, Connecticut, which claimed 26 lives, including 20 children, the Obama administration initiated but failed to push stronger gun control laws.
The laws, whose sections included expanded background checks and bans on assault weapons, were stymied in Congress after staunch opposition from Republican lawmakers and gun-rights lobby groups.
The gunman, identified by authorities as Omar Mateen of Port St. Lucie, Florida, was found dead inside the nightclub after a shootout with the police.
Then the suspect went back into the club to continue shooting and took hostages.
About three hours after the shooting first broke out, police shot and killed the suspect during actions to rescue the hostages.
"It appeared he was organised and well-prepared," said Orlando Police Chief John Mina at an earlier press conference, adding that the suspect had an assault-type weapon and a handgun.
Islamic State (IS) terrorist group has claimed the responsibility for the shootings.
In a message published on the group’s semi-official news agency, Amaq, it described gunman Omar Mateen as a “soldier of the caliphate”, The Telegraph (UK) reported.
Although the statement did not clarify Mateen’s relation to the group, but the language appeared to suggest he was viewed as a lone wolf attacker.