At least 68 people have been killed after flash floods swept through parts of central Texas.
Kerrville County Sheriff Larry Leitha confirmed that 59 people, including 21 children, have been killed in the county, as other deaths have been reported across the state.
Leitha added that 11 Camp Mystic campers and one councillor remain unaccounted for.
Texas Governor Greg Abbot said authorities will "stop at nothing" to ensure every last missing person is rescued.
In a post on social media, US President Donald Trump said: "These families are enduring an unimaginable tragedy".
At a news conference in Austin, Texas Governor Greg Abbott said that "so many people have been swept into an extraordinary catastrophe" following the floods.
He said a meeting with officials has taken place at a local level, and there's a collaborative effort to address concerns "as quickly as possible".
"We remain in a search and rescue posture right now," he added.
"We will stop at nothing to ensure that every asset, and person and plane, and whatever is needed is going to be involved in the process of rescuing every last person," he said.
Abbott then goes on to sign a disaster declaration.
Trump said he has signed a "Major Disaster Declaration for Kerr County, Texas, to ensure that our Brave First Responders immediately have the resources they need".
In a post on social media platform Truth Social he said the families of the dead and missing are "enduring an unimaginable tragedy".
Trump reiterated that his administration continues to work closely with state and local Leaders.
He added that "Secretary of Homeland Security Kristi Noem was on the ground yesterday with Governor Greg Abbott, who is working hard to help the people of his Great State".
"Our incredible U.S. Coast Guard, together with State First Responders, have saved more than 850 lives," he said, ending the message with: "GOD BLESS THE FAMILIES, AND GOD BLESS TEXAS!"
