At least four individuals lost their lives when harsh weather, which possibly included two tornadoes, struck St. Louis, Missouri, on Friday afternoon, officials reported.

Mayor Cara Spencer announced the fatalities during a news conference. She said two of the dead were killed in North City, were a vortex was reported.

Fire Chief Dennis Jenkerson said severe weather hit about 20 square blocks of the city.

A tornado allegedly tore off rooftops and brought down walls in St. Louis, Missouri, on Friday, resulting in children being hospitalized for injuries and prompting a rescue effort for a man, according to authorities.

The tornado was observed after 2:30 p.m. in the vicinity of Forest Park in the city, moving eastward towards Granite City, Illinois, stated National Weather Service meteorologist Marshall Pfahler.

Its force level is unlikely to be known until Saturday when weather service spotters are able to get to the scene and measure damage, tracks and other elements of the vortex, he said.

NBC affiliate KSDK of St. Louis reported that it may have been one of two tornadoes to touch down in the region on Friday. The National Weather Service confirmed that it was working to confirm a second reported tornado in the region.

A spokesperson for St. Louis Children’s Hospital said it has received 10 patients with weather-related injuries, one of whom is in critical condition. The others were reported in fair condition. Parents were reuniting with at least some of the patients late Friday afternoon, the spokesperson said.

KSDK reported an ongoing operation to rescue a man at a severely damaged home in the city. It was most likely smashed by one of the two possible tornadoes or the severe weather’s associated potent winds in the area Friday, the station said.

The man had sought to shelter in the home and ended up stuck inside, possibly in a pantry, after the weather all but destroyed the structure, KSDK said.

St. Louis city officials and police asked the public to stay put on Friday as they respond to the storm’s effects including some reported but unconfirmed injuries.

Utility Spire energy, which serves 1.7 million customers in the region, said there is “severe damage” to homes. Video of the damage showed toppled brick walls and downed tree limbs and power lines in the region.

The nearby city of Clayton said its City Hall is closed as it coordinates a response to the severe weather.

The worst of the weather seemed to have passed St. Louis late in the afternoon, although federal forecasters said a dry night could be followed by the return of thunderstorms on Saturday.

The vortexes were products of a fast-moving low pressure system headed east-northeast from its location over parts of Illinois, Indiana, Kentucky and Missouri, a region under tornado watch until 10 p.m.

The cool, winter-like storm is clashing with a heatwave to the southwest, producing unstable air and eruptions of thunderstorm activity.