A hot air balloon carrying at least 16 people caught fire and crashed in a field in central Texas Saturday morning, officials said, adding that there were no survivors. 

Officials with the Texas Department of Public Safety told the Austin American-Statesman newspaper that 16 people were killed when the balloon crashed in Lockhart, about 30 miles south of Austin.

However, federal investigators would not confirm the exact number of deaths. Erik Grosof of the National Transportation Safety Board would only say that there were "a number of fatalities."

Caldwell County Sheriff Daniel C. Law told The Associated Press that it's the kind of situation where people can walk up and buy a ticket, unlike an airplane, which would have a list of names.

Late Saturday, two officials told the Associated Press that the balloon was operated by Heart of Texas Hot Air Balloon Rides, which is based in New Braunfels, outside of San Antonio. Local media outlets identified the pilot as Skip Nichols, who owned the business and was believed to be in his late-40s. 

Saturday's crash appears to be one of the worst balloon disasters, possibly the worst in U.S. history. The deadliest such disaster happened in February 2013, when a balloon flying over Luxor, Egypt, caught fire and plunged 1,000 feet to the ground, crashing into a sugar cane field and killing at least 19 foreign tourists.

Saturday's crash happened at about 7:40 a.m. in an area that is mostly farmland, with corn crops and grazing cattle. Cutting through that farmland is a row of massive high-capacity transmission lines about 4 to 5 stories tall. The site of the crash appears to be right below the overhead lines, though authorities haven't provided further details about what happened.

Margaret Wylie lives about a quarter-mile from the crash site and told the AP that she was letting her dog out Saturday morning when she heard a "pop, pop, pop."

"I looked around and it was like a fireball going up," she said, noting that the fireball was located under large power lines and almost high enough to reach the bottom of them.

Wylie, who called 911, said the weather seemed clear and that she frequently sees hot air balloons in the area.

A couple driving near the site of the crash told the American-Statesman they saw the balloon just before it crashed and were concerned that it was flying too low. 

"They were hovering in the tree line, and it was barely moving,” Joe Gonzales told the paper. “The flame was really bright like they were trying to go up."

Gonzales estimated that he and his wife drove within 600 yards of the balloon and said he noticed what appeared to be a large number of people on board. 

"I’d never seen one like that with that many people,” he said. “It just didn’t look right."

Heart of Texas' website says the company has balloons that can transport up to 24 people. 

The NTSB's Grosof said at a news conference that the agency has deemed it a major accident and a full-bore investigation will begin Sunday when more federal officials arrive.

Robert Sumwalt, who will head the NTSB's crash investigation team, said he was studying the board's recommendations to the FAA based on previous hot air balloon crashes. Sumwalt, who spoke to the AP while waiting to board a plane to Texas, said the team was still trying to gather basic information about the accident.

Texas Gov. Greg Abbott asked in a statement for "all of Texas to join us in praying for those lost.".

The Associated Press contributed to this report.