Amazon said it was "deeply saddened" by the deaths of at least two workers at an Illinois warehouse on Friday night.
"Our thoughts and prayers are with the victims, their loved ones, and everyone impacted by the storm," spokesperson Kelly Nantel told FOX Business. "We also want to thank all the first responders for their ongoing efforts on scene. We’re continuing to provide support to our employees and partners in the area."
In a pair of tweets later in the day, Amazon CEO Andy Jassy said the company's leadership had been "closely monitoring the terrible situation in Edwardsville," and "are heartbroken over the loss of our team members."
He said their thoughts were with the families of the deceased.
"As this situation continues to evolve, I want our Edwardsville community to know we are working closely with local officials & first responders to support them. My deepest sympathies are with the Amazon community and all impacted," wrote Jassy.
The workers were killed and others injured when the Edwardsville fulfillment center collapsed – including a wall the length of a football field – during a severe storm in the St. Louis area.
It wasn't immediately clear whether the damage had been caused by straight-line storms or a tornado, but the National Weather Service office near St. Louis reported "radar-confirmed tornadoes" in the Edwardsville area around the time of the collapse.
Local emergency responders called it a "mass casualty incident," and around 100 emergency vehicles descended on the area.
The families of the victims were being notified early Saturday, according to the Edwardsville Police Department.
Two people at the facility were transported by helicopter to hospitals in St. Louis, and Edwardsville Police Chief Mike Fillback said he did not know their medical conditions.
As many as 50 to 100 employees were believed to be inside the building, according to Fox 2's Amelia Mugavero, and officials said 30 people had been bused to Pontoon Beach, Ill., to be reunited with family.
"My prayers are with the people of Edwardsville tonight, and I've reached out to the mayor to provide any needed state resources," Illinois Gov. J.B. Pritzker said in a Twitter statement. "Our @ILStatePolice and @ReadyIllinois are both coordinating closely with local officials and I will continue to monitor the situation."
Tornadoes and severe storms hit several Midwest and southern states overnight, including Missouri, Arkansas, Kentucky and Tennessee.
At least seven people were killed, although dozens more are feared dead, according to Kentucky Gov. Andy Beshear.
About 110 people were in a candle factory in Mayfield, Ky. when a tornado hit.
"We believe our death toll from this event will exceed 50 Kentuckians and probably end up 70 to 100," he told reporters on Saturday. "It’s very hard, really tough, and we’re praying for each and every one of those families."
Western Kentucky University's president said on Twitter that one of its students who live off-campus was killed.
Additionally, one person died and two were injured in Missouri, a person was killed and 20 people were trapped at an Arkansas nursing home and three storm-related deaths were confirmed in Tennessee, according to a spokesperson for the Tennessee Emergency Management Agency.
President Biden tweeted that he had been briefed on the situation and pledged the affected states would "have what they need as the search for survivors and damage assessments continue."
Fox News' Brie Stimson, Dom Calicchio and The Associated Press contributed to this report.