More than two dozen victims remain in hospital and six are in critical condition after the attack on the Pulse nightclub in Orlando, where a gunman killed 49 and left dozens injured on Sunday in the worst US terrorist attack since September 11, 2001.
Some 27 patients were still in the Orlando Regional Medical Centre on Tuesday, with six in the intensive care unit, Doctor Mike Cheatham said at a press conference detailing the chaotic scene at the hospital after a gunman opened fire in the gay nightclub.
No patients had died in hospital since the night of the attack, but Cheatham said the death toll could still rise even as most patients were "steadily improving."
A team of trauma surgeons described patients arriving in "truckloads" and said they quickly assessed them as they called in additional doctors. At one point, the team ran out of operating supplies amid the high volume of patients.
The situation was "what you would think of a war scene," Doctor Joseph Ibrahim said, describing a whole range of injuries.
Many of the victims were able to survive because the hospital is just a few city blocks away from the nightclub, doctors said.
Victims described the chaos at the club just before closing time as shots range out and the gunman roved the dance floor and restrooms shooting people to be sure they were dead.
"All I could do was just lay there while everyone walked over me," survivor Angel Colon said. "All I could hear was the shotgun and people just calling for help."
The gunman, Omar Mateen, appeared to have been self-radicalized from Islamist material online, US President Barack Obama said.
Obama was briefed again Tuesday on the investigation by his national security team as part of a broader anti-terrorism meeting on the US efforts against Islamic State.
After the meeting, he renewed calls for tougher US gun laws and blasted Republicans, including Donald Trump, for focusing on his word choices when discussing terrorism instead of addressing the issue.
Mateen, a 29-year-old US citizen, pledged allegiance to the Islamic State terrorist group in an emergency call while the attack was under way, but the FBI also said he had praised other competing terrorist groups, such as al-Nusra Front.
Reports Tuesday also said that Mateen had been a regular at the nightclub and had also surveilled Disney World as a potential target. Questions also emerged about Mateen's wife and her knowledge of his plans.
The attacker had been investigated by the FBI twice before, including for remarks he made to coworkers in 2013 claiming affiliations with al-Qaeda and Hezbollah.