A funnel cloud is seen in Homer Glen, Illinois, US. Photograph:( Reuters )
'The storm system is weakening as it pushes into West Virginia and Virginia, but along with the winds, it has dropped about two or three inches of rain in just two hours,' he said.
A tornado slammed into the US city of Dayton, Ohio on Monday as severe storms were forecast to pound the area overnight, officials and media reports said.
At least two other tornadoes touched down near the city, including one near Wright-Patterson Air Force Base, just east of Dayton, media reports said.
The latest storm comes after a spate of tornadoes and floods killed at least six people in Oklahoma over the weekend, including two people in El Reno, near the state capital on Saturday.
In Ohio, the extent of the damage and injuries was not immediately clear.
"We're right in the middle of it right now. It's a mess," said a phone operator with the Office of Emergency Management in Montgomery County.
Some media outlets reported that rescue workers were going door-to-door in parts of Dayton. Police and sheriff's departments were not immediately available for comment.
Twitter users posted images of debris flying in the air and damaged mobile homes and cars.
The National Weather Service said that there were reports of multiple tornadoes in the Dayton area between 11 p.m. Monday and 1 a.m. Tuesday.
"We'll have to get survey crews on the ground in the morning to confirm the severity of the storms, but yes, there is at least one tornado touch down in the city," said Zack Taylor, a meteorologist with the NWS Weather Prediction Center in College Park Maryland.
"The storm system is weakening as it pushes into West Virginia and Virginia, but along with the winds, it has dropped about two or three inches of rain in just two hours," he said.
Flooded areas of Arkansas and Oklahoma were bracing for more rain that will feed the already swollen Arkansas River, forecasters said on Monday, as Missouri deployed the National Guard in anticipation of further storms.
Arkansas and Oklahoma have also activated National Guard units.
Millions of Americans were under flood warnings on the Memorial Day holiday with Kansas, Nebraska, Iowa and Illinois getting a deluge while Oklahoma and Arkansas got a reprieve for the most part.
In Tulsa, officials were monitoring the Arkansas River after the US Army Corps of Engineers raised the flow at the upriver Keystone Dam by 65% since last week to 275,000 cubic feet per second. The heavier flow is testing two ageing levees in Tulsa, the city said.
In neighbouring Missouri, Governor Mike Parson on Monday activated the National Guard to respond to flooding and prepare for severe storms this week, his office said in a statement.
Tornadoes and severe storms that slammed into the state last week killed three people and destroyed or damaged hundreds of homes.