At least 116 people have been killed following a massive tornado that swept through the Midwestern US city of Joplin in Missouri.
Emergency officials announced the latest death toll on Monday, saying that about 400 other people were injured in the twister. Many of those wounded were reported to have massive internal injuries, according to local officials.
The tornado struck the city near the border with Oklahoma and Kansas on Sunday evening, less than a month after a horrific tornado outbreak left 354 dead across seven US states.
The twister was the deadliest of 46 tornadoes reported to the National Weather Service in seven states on Sunday.
Fire chief Mitch Randles estimated that 25 to 30 per cent of the city was damaged by the tornado.
"It cut the city in half,'' Randles said.
Meanwhile, Scott Meeker of the Joplin Globe newspaper said the tornado turned the city into a "war zone".
"We've got hundreds of wounded being treated at Memorial Hall (hospital), but they were quickly overwhelmed and ran out of supplies, so they've opened up a local school as a triage centre," added Meeker, who is a resident of the town.
People clawed through the rubble looking for friends, family and neighbours after the storm tore buildings apart and turned cars into crumpled heaps of metal.
Flames and thick black smoke poured out of the wreckage of shattered homes, and water gushed out of broken pipes as shocked survivors surveyed the damage, early photos showed.
Many streets on the city's south side were described as impassible, littered with downed trees and utility poles. Emergency vehicles were racing across the city, taking injured residents to hospitals.
Phone communications in and out of the city of about 50,000 people, about 257km south of Kansas City, were largely cut off.
St John Regional Medical Center was evacuating nearly 100 patients after the hospital took a direct hit from the tornado, Cora Scott, a spokeswoman at the hospital's sister facility, said.
The patients were being taken to other hospitals. Witnesses said windows were blown out on the top floors of the hospital.
Jeff Lehr, a reporter for the Joplin Globe, said he was upstairs in his home when the storm hit but was able to make his way to a basement closet.
"There was a loud huffing noise, my windows started popping. I had to get downstairs, glass was flying. I opened a closet and pulled myself into it," he said.
"Then you could hear everything go. It tore the roof off my house, everybody's house. I came outside and there was nothing left."
Lehr said people were walking around the streets outside trying to check on neighbours, but in many cases there were no homes to check.
"There were people wandering the streets, all mud covered," he said. "I'm talking to them, asking if they knew where their family is. Some of them didn't know, and weren't sure where they were. All the street markers were gone."
Resident Tom Rogers walked around viewing the damage with his daughter.
"Our house is gone. It's just gone," Rogers told the Joplin Globe. "We heard the tornado sirens for the second time. All of a sudden, everything came crashing down on us. We pulled our heads up and there was nothing. It was gone."
State of emergency
Missouri governor Jay Nixon activated the National Guard and declared a state of emergency. Nixon said the state and local law enforcement agencies were co-ordinating search and rescue and recovery operations.
Tammy Spicer, a Missouri National Guard major, said more than 100 members of the 35th Engineer Brigade, which has a battalion based in Joplin, were expected to immediately report for duty to aid in search and rescue efforts, clear roads, provide security and help with radio communications.
The guard's armoury in Joplin suffered only minor damage but was without electricity Sunday night, Spicer said. One of the challenges facing the guard was simply getting in touch with all of its members in the area, she said.
"This just looks like a horrific event," Spicer said. "We want to help the community - both the emergency response forces there and the citizens."
In Minneapolis, Sara Dietrich, a city spokeswoman, said the death there was confirmed by the Hennepin County medical examiner. She had no other immediate details. Only two of the 29 people injured there were hurt critically.
Though the damage covered several blocks in Minneapolis, it appeared few houses were totally demolished. Much of the damage was to roofs, front porches that had been sheared away, or smaller items such as fences and basketball goals.
In Wisconsin, a powerful storm caused significant damage in La Crosse, tearing roofs from homes and sending emergency responders to search damaged buildings for anyone trapped inside, officials said.
La Crosse County sheriff's dispatcher Tim Vogel described the damage as "significant" but told The Associated Press news agency there were no immediate reports of serious injuries.
Sunday's storms followed a tornado on Saturday night that swept through a small eastern Kansas town, killing one person and destroying at least 20 homes, as severe thunderstorms pelted the region with hail that some residents described as the size of baseballs.
US president Barack Obama on Monday sent his "deepest condolences" to victims of tornadoes that have struck the Midwestern cities.
"Michelle and I send our deepest condolences to the families of all those who lost their lives in the tornadoes and severe weather that struck Joplin, Missouri, as well as communities across the Midwest today," the president said in a statement sent from Air Force One as he was flying to Europe.
"We commend the heroic efforts by those who have responded and who are working to help their friends and neighbours at this very difficult time," Obama added.
Obama said the federal government stood ready to aid Americans as needed.