At least six Amazon workers have been killed at a warehouse in the US after a series of devastating tornadoes hit the country.
Deadly storms struck on Friday night, ripping off the roof the building in Edwardsville, Illinois, and reducing a wall longer than a football field to rubble.
Several workers remained unaccounted for as rescuers searched for anyone who might still be trapped at the facility, authorities said.
Fire chief James Whiteford said 45 people had made it out safely as of Saturday afternoon.
He said six people were confirmed killed so far, and he expected recovery efforts to last for at least three more days.
Colleagues and family members desperate for news about loved ones gathered outside the 500,000 square foot mess of concrete and steel.
Amazon truck driver Emily Epperson, 23, said she was anxiously waiting for information on the whereabouts of her workmate Austin McEwan late Saturday afternoon to relay to his
girlfriend and parents.
"We're so worried because we believe that, you know, he would have been found by now," she said.
One mother told a St Louis Fox news station that her son Clayton Cope, a 29-year-old maintenance worker, was dead.
Police have yet to officially release names.
Earlier reports said about 50 workers were believed to be at the warehouse when it was hit by an extreme "weather-related event" about 8:30pm local time on. Friday.
A devastating swarm of tornadoes ripped through six states, leaving a trail of death and destruction at homes and businesses that stretched more than 200 miles.
At least 30 workers were transported by bus from the scene but others may have left on their own.
Police Chief Mike Fillback said it had been difficult to get an exact number of workers who might be unaccounted for because the warehouse did not have "a set staff."
"You have concrete, and you have things hanging. It's quite windy outside, so things are unstable, so they have to shore those things up so that they can be safe," Chief Fillback said.
"Our first responders will continue to work this scene until everyone is accounted for."
Drone footage from the scene showed rescue workers picking through a huge area of debris in the pre-dawn darkness.
Amazon CEO Andy Jassy posted on Twitter that the company was "heartbroken over the loss" of its staff members and would continue to work closely with the local authorities on the rescue efforts.
"It gives me shivers," Kathie Burnett, 67, said. She was a delivery driver at Amazon until two weeks ago when she quit because of health reasons.
"I would have been standing right in the middle of that track," she said pointing to what remained of the facility.
"There would have been 100 trucks in there last night and you didn't see one this morning, did you?"
