The storms are part of a severe weather system sweeping across the Midwest, leaving thousands without power.

At least 21 people have died after tornadoes caused by severe storms swept through the states of Missouri and Kentucky in the United States, officials said.

Kentucky governor Andy Beshear on Saturday said on X that at least 14 people died in the Friday night’s storms.

At least seven others were killed in Missouri as authorities launched a search for people trapped in buildings.

Kentucky authorities said there were severe injuries when a tornado tore across Laurel County late on Friday. “The search is continuing in the damaged area for survivors,” the office of Sheriff John Root said in a statement posted on social media.

In Missouri, St Louis Mayor Cara Spencer confirmed five deaths in her city and said more than 5,000 homes were affected.

“Our city is in mourning tonight,” she told reporters. “The loss of life and destruction is truly, truly horrific.”

Another tornado struck Scott County, about 209km (130 miles) south of St Louis, killing two people, injuring several others and destroying multiple homes, Sheriff Derick Wheetley wrote on social media on Friday.

“Our first responders acted swiftly, even while the tornado was still active, putting themselves in harm’s way to provide immediate assistance and care to those injured,” he said.

The storms, which began on Friday, are part of a severe weather system that has also spawned tornadoes in Wisconsin, leaving thousands of people without power in the Great Lakes region and bringing a punishing heatwave to Texas.

A dust storm warning was issued around the Chicago area on Friday night. The weather service said a wall of dust extended along a 161km (100-mile) line from southwest of Chicago to northern Indiana that severely reduced visibility.

In Texas, a heat advisory was issued for San Antonio and Austin cities, with temperatures at a blistering 95F (35C) to 105F (40.5C). Parts of the southern East Coast, from Virginia to Florida, also battled with heat in the 90s (32-37C).

The National Weather Service Office for Austin and San Antonio said humidity over the weekend was expected to make temperatures feel hotter.

“There are concerns of heat exhaustion for people that aren’t taking proper precautions when they’re outdoors,” meteorologist Jason Runyen said, advising those affected to take breaks and stay hydrated.