Walt Disney World resort in Florida closed its beaches on Wednesday as police hunted for a 2-year-old boy who was dragged by an alligator into a lagoon in front of his family despite an attempt by his father to rescue him.
Wildlife officials captured and euthanized four alligators from the lagoon to examine them for traces of the child after the attack on Tuesday night but found no evidence they were involved, said Nick Wiley, head of the Florida Fish and Wildlife Conservation Commission.
There are "no swimming" signs at the lagoon but the alligator grabbed the boy as he played at the water's edge while his family relaxed nearby on the shore, sheriff's spokesman Jeff Williamson told a news conference.
The boy's father rushed into the water after the alligator struck and fought to wrestle his child from the large reptile's grasp, Williamson said.
"The father did his best," Williamson said. "He tried to rescue the child, however, to no avail."
Jerry Demings told reporters the reptile was thought to be between 4 and 7 feet (1.2 and 2 metres) long.
The father suffered minor cuts on his arm in the struggle with the gator, Williamson told reporters. Authorities had earlier said the boy's mother tried to rescue him too.
A lifeguard who was on duty by the lagoon also was unable to reach the boy in time.
"The gator swam away with the child," Williamson said.
The family, which was vacationing from Nebraska, was not named.
Disney has meanwhile closed its beaches and recreational marinas, a Disney representative said.
Dozens of sheriff's deputies and wildlife officials were searching for the boy on Wednesday and expected to use sonar technology, helicopters and a team of divers.
Alligators are not uncommon in the Seven Seas Lagoon, a man-made lake reaching 14 feet in depth, Wiley said. The wildlife commission works with the resort to remove "nuisance alligators" when they are reported.
The upscale Grand Floridian Grand Resort and Spa is described by Disney as a lavish property where Victorian elegance meets modern sophistication, just one stop away from the Magic Kingdom on the resort's monorail.
A spokeswoman for Walt Disney World Resort said everyone there was devastated by the tragic accident.
"Our thoughts are with the family and we are helping the family," she said.
Despite the prevalence of alligators in fresh water around Florida, Wiley said it was very rare for humans to be attacked.
In May, a Florida man was hospitalized after an alligator bit off his hand and forearm as he sought to elude authorities by running into a lake, according to police.
Williamson said searchers had been hindered overnight by the dark and by the lagoon's murky waters. "We're going to keep searching until we find something," he said.
The alligator incident comes as the Orlando area reels after a gunman killed 49 people at a gay nightclub there on Sunday before dying in a gun battle with police.
It also follows an incident on May 28 when a 3-year-old boy fell into a gorilla enclosure at the Cincinnati Zoo, causing zookeepers to kill a gorilla to protect the child.