Multiple tornadoes have struck the US state of Ohio, causing injuries and extensive damage.
Some five million people have been left without power due to the tornadoes, which began late on Monday night.
Injuries were reported around the cities of Dayton and Celina, but exact numbers were not immediately clear as rescue efforts continued.
Dayton Fire Chief Jeff Lykins told the BBC they were “extremely fortunate to have no reported deaths at this point.”
“We do not yet have a full appreciation for the extent of damage from the tornadoes but expect to know more once the sun comes up,” he said. “At this moment, we expect that we will find significant, widespread damage”.
The National Weather Service (NWS) said it would be conducting damage surveys in several locations across Ohio in the coming days.
At about 23:00 (03:00 GMT), the NWS confirmed that a “large and dangerous tornado” was on the ground near the city of Trotwood, which is part of Greater Dayton.
Throughout the night, the NWS issued multiple warnings for people to take cover, stressing that it was a “life threatening situation”.
Following the tornadoes, the NWS said there were more than 70,000 power outages in Ohio, affecting some five million people.
Authorities in Dayton said the local water plants and pump stations were among those that had lost power as they urged people to conserve water.
The calls came as search and rescue operations got under way, with emergency services working to clear the debris left by buildings destroyed by the tornadoes.
Trotwood Mayor Mary McDonald said there were “lines and trees down”, as she called on people to stay safe.
She confirmed to local media outlets that several people had been injured as a result of the extreme weather.
Mercer County Emergency Management Agency Director Mike Robbins told the BBC that seven people had been injured in Celina, with three in a serious condition.
Beavercreek, a Dayton suburb, issued an emergency declaration.
“Areas are being closed, many gas leaks also reported. Please stay out for your safety and others. We are still in the search and rescue mode,” the police department wrote on Facebook.
Montgomery County, which includes Dayton, said Red Cross shelters had been set up across the region, offering water and food.
The US’s Southern Plains and Midwest regions have been hit by several tornadoes, as well as severe rains and flooding in recent days.
Two people were killed in Oklahoma over the weekend when a tornado tore through a hotel and mobile home park in the city of El Reno.