Torrential rains and flooding have killed at least 13 people in the United States and left some 170,000 homes and businesses without power from Texas to Mississippi, authorities say.
US officials said on Tuesday that 12 people were missing in Texas after the vacation home they were staying in was swept away by rushing floodwaters.
The storms battered the US Gulf Coast states - largely Texas and Oklahoma - during the Memorial Day weekend.
Authorities confirmed the deaths of 13 people— 10 adults and three infants.
Two deaths happened in Houston where flooding turned streets into rivers and led to nearly 1,000 calls for help.
"There are still some significant areas of really devastating flooding in Houston," Mayor Annise Parker said at a news conference.
Parker added that she called on Texas Governor Greg Abbott to declare the city a disaster area.
Abbott has declared a state of disaster in 24 Texas counties.
US President Barack Obama said that he had assured Abbott that "he could count on the help of the federal government” as Texas struggles with the floods.
“I will anticipate that there will be some significant requests made to Washington. My pledge to him is that we will expedite those requests,” Obama told reporters in the Oval Office.
The US National Weather Service issued a flash flood warning on Tuesday for Houston as a line of thunderstorms moved along the Gulf of Mexico coast toward Florida.
The warning said more rain and thunderstorms are expected in Texas this week.
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