At least 16 die in freak storms in Texas and Oklahoma - with more deaths expected

Torrential rains and flash floods have claimed at least 16 lives in Texas and Oklahoma this week - and the death toll looks set to rise.

Numerous people are still missing in Texas after storms blasted the state over Memorial Day weekend, turning roads into rivers and forcing thousands of evacuations.

More than 1,000 vehicles have been submerged by floods in Houston, while bridges have been swept away. The power of the water even unearthed a coffin, which was found floating in a bayou.

Twelve people are confirmed missing and about another 30 are unaccounted for due to flooding that hit along the Blanco River, county officials said. The missing were from two families whose vacation home was swept off its foundation in Wimberley, a town about 30 miles southwest of Austin.

The Houston Fire Department brought about 500 people to safety in boats, local media reports have said.

President Barack Obama said on Tuesday that he had assured Texas Governor Greg Abbott that he could count on help from the federal government as the state recovers from the floods.

Abbott has declared a state of disaster in at least 40 Texas counties.

"It's devastating to see what I saw on the Blanco River when this tidal wave of water just swept away neighborhoods," he said, recalling a disaster area in central Texas.

No estimate of the cost of the damage has so far been produced, but the National Weather Service has issued more severe weather warnings, while more than 200 flights have been cancelled in Houston and Dallas.