US President Donald Trump said federal cash for storm-ravaged areas in Texas and elsewhere will arrive quickly.
He said to people suffering from Hurricane Harvey and the resulting flooding that "you're going to have what you need and it's going to go fast".
Mr Trump added that he has spoken with members of Congress and "everybody feels for" people in the storm's path.
The storm has dumped historic amounts of rain on areas in and around Houston, which continues to flood.
It is the first major natural disaster of Mr Trump's presidency.
The president also told flooding victims via a press conference on Monday that "we are 100% with you".
He added: "We will get through this. We will come out stronger and believe me we will be bigger, better, stronger than ever before."
Mr Trump is expected to visit the Houston region on Tuesday.