The three people aboard the Amazon Prime Air cargo plane that crashed outside Houston have been confirmed dead, the plane's operator said Sunday.

The Boeing 767 operated by Atlas Air was a scheduled cargo flight for Amazon from Miami to Houston on Saturday when it nosedived into a swampy area about 30 miles from George Bush Intercontinental Airport.

"It is with great sadness that Atlas Air Worldwide has confirmed that the three people on board ... did not survive the accident," the company said in a Sunday afternoon statement.

Atlas CEO Bill Flynn, who is at the crash site with other company representatives and federal, state and local investigators, said Atlas is setting up assistance programs for the family members of the those killed in the crash. Authorities have not yet released their names.

"Our thoughts and prayers are with all those who have been affected,” Flynn said in a statement. "This is a sad time for all of us. Our team continues to work closely with the NTSB, the FAA and local authorities on the ground in Houston. We would like to commend the efforts of all of the first responders. We sincerely appreciate their efforts and support in the investigation."

Chambers County Sheriff Brian Hawthorne on Saturday asked for anyone with video or pictures of the crash to submit them to investigators.

Witnesses said they heard the plane’s engines surging and watched the craft turn sharply before falling into a nosedive, Hawthorne said.

Federal investigators are helping local authorities search the wreckage for the plane's flight recorders, which could help explain the crash. Investigators say the crash left debris strewn across a wide area of Trinity Bay.

AccuWeather meteorologists suggested weather could be to blame: "There were a few showers with gusty winds in the vicinity of Houston at the time of the crash. While an investigation needs to take place, these were around the area and could have been a factor in the crash," AccuWeather Senior Meteorologist Alan Reppert said.

Investigators say they're using a mix of boats and airboats to search the swampy, marshy area. People who worked nearby were among the first to reach the wreckage, KHOU-TV reported.

“The whole reason for us going out there was to see if we could save anybody," boat mechanic Jason Campbell told the TV station. “There’s not much of a plane left to tell that it was actually an airplane. There’s packages, clothes, shoes, this stuff floating everywhere.”