Media playback is unsupported on your device Media caption Footage showed cars being washed away and the aftermath of flooding in the US

At least five people have died and hundreds of homes have been destroyed in flash flooding in the southern US.

Two people were killed in weather-related accidents in Oklahoma and three lost their lives in San Marcos, Texas.

Some areas saw up to 10 inches (25cm) of rain over a 24-hour period, with more predicted across the region.

Twelve people, including two children, were reported missing along the Blanco river in Texas, local media report.

Texas governor Greg Abbott said it was the worst flooding the state had seen, and that he had observed the devastation from the air.

"You cannot candy coat it, it's absolutely massive and I think it sends a powerful message to anyone who is in harm's way over the entire state of Texas over the coming days as we see ongoing rain, and that is the relentless tsunami-type power that this wave of water can pose for people," he said.

'Praying for the best'

Jonathan McComb was staying at a house in Wimberley with his wife and their young son and daughter when they were swept away.

Mr McComb was taken to hospital with serious injuries, but his family has not yet been found. Five others were also reportedly dragged away by the floodwaters.

His father, former county commissioner Joe McComb told Kiii TV: "It is in the Lord's hands... we're praying for the best."

Three deaths have been linked to the flooding in Texas since Saturday, the latest being a 14-year-old boy who was found with his dog in a storm drain in Dallas.

There were numerous rescues on Sunday after banks burst, and hundreds of homes were destroyed across the region.

Warnings and alerts stretch from Colorado through to Arkansas, Louisiana, Missouri and eastern Kansas.

The Blanco is one of the worst hit rivers in Texas. At one point it crested at 43ft (13m) - some 30ft above the designated flood stage and 7ft higher than the 1929 record.

Image copyright AP Image caption The Blanco river basin in Texas is one of the worst hit areas

Image copyright AP Image caption Highway patrolmen used air boats for rescues in Purcell, Oklahoma

Image copyright AP Image caption Several hundred houses have been destroyed in Wimberley

A flash flood emergency - reserved for the most life-threatening situations - is in effect in the river basin area.

Some 1,000 people nearby were evacuated from their homes and parts of the Interstate 35 highway were flooded and closed.

Tornado warnings

Kristi Wyatt, communications director for the town, said: "We have people on car tops and rooftops awaiting rescue. People in homes are going to higher levels."

She said hundreds of people were now in evacuation centres and that floodwaters had washed away five police cars.

A tornado hit Houston briefly on Sunday, damaging buildings and injuring at least two people.

Warnings of more tornados have been issued for parts of Iowa, Kansas, Missouri and Illinois.

Image copyright AP Image caption Flood victims are rescued in Kyle, Texas

Image copyright AP Image caption A couple in Oklahoma had to make three trips to rescue their pets

In parts of San Antonio water exploded from sewer covers.

A mandatory evacuation was ordered at Lake Lewis, 50 miles (80km) north of Houston, which itself saw high winds bringing down trees and blowing out windows.

Residents in Wichita Falls, also in Texas, were warned the Wichita river could burst its banks.

A fire-fighter died in Oklahoma when he was swept away while taking part in a rescue effort in the town of Claremore, in the north-east of the state. He was named as Capt Jason Farley.

A woman was also killed in a weather-related traffic accident in Tulsa.

Residents were rescued from roofs in the state's Cleveland and Comanche counties.

The National Weather Service says Oklahoma City already has a new monthly rainfall record for May - at 18.19 inches.

In Colorado, El Paso and Pueblo counties and the city of Sterling were badly affected.