At least two people were killed and several others injured when a tornado tore through El Reno, Oklahoma, the city's mayor, Matt White, said Sunday.
"It's been a serious, serious event here," White said in a press conference. "We have all hands on deck."
Search and rescue teams are still combing through the rubble left behind after the tornado hit the city on Saturday, the mayor said.
The injured were transported to hospitals, White said, without providing figures on the number of people hurt.
The tornado hit the city around 10:30 pm and moved across El Reno on a southwest to southeast track, the mayor said.
Media reports said the deaths occurred at a mobile home park in the small city, which was battered by another twister on May 31, 2013.
"It's a tragic scene out there," White said. "People have absolutely lost everything."
The tornado leveled a motel and television stations aired video of emergency services personnel digging through the rubble.
Police in neighboring Union City said on the department's Facebook page that the situation was dangerous.
"Severe damage with serious injuries and fatalities involved ... This is an unfortunate example of just how quickly these types of storms can develop from a simple thunderstorm into a deadly supercell tornado," the law enforcement agency said.
National Weather Service (NWS) radar showed objects and debris being hurled some two kilometers (1.2 miles) by the tornado.
The Weather Channel, meanwhile, reported that another tornado hit Tulsa, the second-largest city in Oklahoma, causing property damage.
PowerOutage.us, a website that tracks power outages across the country, said about 37,000 customers were without electricity on Saturday night in the areas affected by the twisters.
Last week, tornadoes affected several states in the Midwest, killing at least three people in Golden City, Missouri, located about 100 kilometers (62 miles) southwest of Jefferson City, the state capital.
A tornado caused extensive damage in Jefferson City, but no one was killed.
Emergency services workers transported about 20 people to hospitals in Jefferson City, but no one had life-threatening injuries, officials said.
The worst damage in Missouri's capital occurred in a nearly five sq. kilometer (1.9 sq. mile) area in the southern part of the city in which several buildings, including a school, were damaged by the twister's powerful winds.