At least 13 killed as tornadoes leave a trail of destruction across three states

At least 13 people have been killed as tornadoes swept across three US states, destroying homes within minutes and leaving hundreds of thousands without power.

Four people died in Arkansas, two in Oklahoma, and seven in Texas, with many more injured.

Sheriff Ray Sappington of Cook County, Texas, reported that the fatalities there included two children, aged 2 and 5, and warned that the number of casualties was likely to rise.

"We're still in search and rescue mode right now. I hope we can still find survivors," he told US media early on Sunday. "It's just a trail of debris left. Sadly we think that number is probably going to go up. The devastation is pretty severe."

The storms in Texas coincided with record-breaking heat in parts of the state, prompting triple-digit temperature warnings over the Memorial Day holiday weekend.

By Sunday afternoon, the storm system had begun moving eastward, with the National Weather Service warning of severe wind and hail for those in its path.

Approximately 470,000 people were without power in states stretching from Texas to Kansas, Missouri, Arkansas, Tennessee, and Kentucky.

In Indiana, the start of the Indianapolis 500 was delayed on Sunday due to storms, with fans being asked to leave their seats and seek shelter.

These latest tornadoes follow another powerful storm that struck a rural town in Iowa earlier in May, killing four people.