At least 25 people have perished in severe weather that swept across Missouri and Kentucky over the weekend, authorities said.

Kentucky Gov. Andy Beshear said the number of weather-related fatalities — he attributed them to a single tornado initially believed to have touched down at EF3 strength overnight — had risen from 14 to 18 by late Saturday afternoon.

“It has taken far too many lives,” Beshear said. “Homes that there isn’t a single wall standing. Homes that have all four walls yet lost the person inside.”

The governor said 17 of the fatalities were in Laurel County and one was in Pulaski County. One of the deceased was a Laurel County firefighter, Beshear said.

Officials in Missouri reported seven weather-related fatalities since Friday, including five in St. Louis County and two in Scott County.

Beshear vowed that the state’s resources are being deployed to help Kentuckians affected by the severe weather. He said 10 people remained in critical condition after suffering weather-related injuries in Kentucky.

A spokesperson for St. Louis Children’s Hospital and Barnes-Jewish Hospital in St. Louis, Missouri, said the facilities received over 60 patients in total, with the children’s facility treating 15 and Barnes-Jewish seeing more than 50. Two of the patients at Children’s Hospital were in critical condition. All others have been discharged, the spokesperson said on Saturday.

Most of the patients at Barnes-Jewish have been discharged or will be soon, the spokesperson said.

St. Louis Mayor Cara Spencer said the severe weather, including two reported tornadoes in the area on Friday, affected an estimated 5,000 buildings in the city.

Homeland Security Secretary Kristi Noem said in a statement Saturday that she has spoken with the governors of Missouri, Kentucky and Illinois and offered them “federal resources and action for the deadly tornadoes and storms.”

“We discussed how while emergency management is best led by local authorities, we reinforced that DHS stands ready to take immediate action to offer resources and support,” Noem said.

The severe weather was the result of an east-moving system of unstable air set off by a clash of warmth to the south and west and a cooler front to the north, federal forecasters said.

The National Weather Service said 28 tornadoes were reported on Friday.

More than 63,000 utility customers in Missouri and 58,000 in Kentucky were without power on Saturday, according to utility tracker PowerOutage.us.