Hundreds of people remain unaccounted for following the catastrophic flash flooding which hit the US state of Kentucky last week.
Governor Andy Beshear made the announcement as he revealed that the number of people known to have died has risen to 37.
In a tweet he said: "We are ending the day with more heartbreaking news out of Eastern Kentucky. We can confirm the death toll has now risen to 37, with so many more still missing. Let us pray for these families and come together to wrap our arms around our fellow Kentuckians."
Earlier in the day he had refused to be drawn on the possible fate of the hundreds of people who are still missing.
"We just don't have a firm grasp on that. I wish we did -- there are a lot of reasons why it's nearly impossible," he said at a news conference.
"But I want to make sure we're not giving either false hope or faulty information."
The rural landscape of creeks and valleys has made access to remote communities extremely difficult.
Roads have been damaged and bridges are down. Communications have also been cut, making it impossible to contact people caught up in the flooding.
The receding waters have allowed rescuers to travel down creeks by boat and recover bodies.
The governor made his comments while visiting another part of the state hit by extreme weather seven months ago.
The community of Mayfield is still rebuilding, and Mr Beshear revealed the astonishing cost of the reconstruction.
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"Based on our estimates of US or Federal, state and Red Cross disaster assistance, we spent $193.4bn into the areas hit by the tornadoes," he said.
"So I know we're going to need a lot more. But I don't think we have ever seen anything like that."
On Sunday, Mr Beshear, a Democratic Party governor of a state that is bitterly politically divided, told Sky News that he worried nothing could withstand such extreme weather.
"Whether it was a tornado or this flood, it's gonna be hard to build infrastructure that withstands it," he said.
On climate change, global warming and the human impact on the planet, he said now was not the time for a wider debate.
"Listen, I believe in climate change, I believe it causes more devastating weather. But my job right now is to get families back together, get a roof over their head and make sure they have enough to eat and that's what I'm focused on.
"Right now, they just want help. They just want to find the relatives, and they don't want their experience to be co-opted in a larger debate."