Updated at 6:15 p.m. ET
President Trump, declaring "there has probably never been anything like this," praised the work done by federal officials and authorities in Texas and Louisiana to deal with the massive flooding caused by Harvey, the hurricane-turned-tropical storm.
"To the people of Texas and Louisiana, we are 100 percent with you," Trump said in his opening statement at a joint news conference with Finnish President Sauli Niinisto.
"We are one American family," he said, adding, "We will get through this. We will come out stronger, and believe me we will be bigger, better, stronger than ever before."
In response to a question about funding for long-term recovery, Trump told Dallas News' Todd Gillman, "You're going to have what you need, and it's going to go fast," saying he had already spoken with members of Congress.
Trump is traveling to Texas on Tuesday, and said he may return to the area on Saturday.
At an earlier briefing in Washington, Federal Emergency Management Agency Administrator Brock Long called the response to Harvey an ongoing situation, adding, "We're not at recovery yet." He told reporters, "This is a life safety, life sustaining mission."
FEMA's boosted response comes a month ahead of Congress' deadline to sort out government spending for the next fiscal year. Trump's May budget recommendation included cuts for some of the agency's disaster mitigation programs.
A wide array of federal agencies, and more than 8,500 federal officials are working in the two states.
FEMA says it had 900 Urban Search and Rescue personnel "working to save lives" in south Texas as of Sunday, part of an overall force of more than 1,800 employees. In addition, the Department of Homeland Security has sent more than 300 employees as part of its surge capacity force. That includes federal law enforcement personnel.
Other federal agencies involved in the Harvey response efforts include the National Guard; the Coast Guard, which has performed some 2,000 rescues; and the Department of Health and Human Services, which has 500 people on the ground in Texas and Louisiana with medical equipment and supplies.
"We need citizens to be involved" as well, Long said, calling the continuing rains a landmark event. "You could not dream this forecast up."
FEMA says it has made available more than 1 million liters of water, along with 1 million meals, more than 20,000 tarps and 70 generators at staging areas in Texas and Louisiana.
But the real test for FEMA will be after Harvey's rains finally cease, and recovery efforts get underway. Long says the agency has already processed over 15,000 calls from people registering for disaster assistance, a fraction of the more than 450,000 it expects.
(People who wish to register for disaster assistance and have Internet access are advised to go to DisasterAssistance.gov, or to call 1-800-621-FEMA.)
In an interview with KTRH Radio in Houston Monday morning, Vice President Pence said officials are expecting the recovery to be a long-term project. "When you look at the magnitude of the flooding that's taken place in the fourth largest city in the United States, that we anticipate that it will be years coming back," Pence said.
Trump has declared Texas and Louisiana disaster areas, making residents eligible for assistance that can include help paying rent for temporary housing as well as repairing or replacing existing homes.
However, as NPR's Greg Allen reported in June, the president's proposed budget would cut federal funds available for some disaster mitigation programs:
"Under that budget, a program that helps states and communities take long-term measures to reduce losses from disasters, the Pre-Disaster Mitigation Grant Program, has been cut by more than 60 percent. The budget also eliminates funding for an ongoing effort to improve and redraw the nation's flood maps."
It's not clear whether Congress will go along with the president's proposed cuts to long-term FEMA programs. Trump said the FEMA money "was very small," compared to the many billions he said will be needed from Congress to help the storm-affected areas recover.
In addition to his proposed budget cuts, Trump announced an executive order on Aug. 16 rolling back an Obama-era rule that new public infrastructure projects be designed with climate change, specifically rising sea levels and flood risk, in mind. FEMA had still been gathering feedback on the rules, which had not gone into effect. Denounced by environmental groups as "climate science denial," Trump and business advocates considered the rules unnecessarily burdensome and costly.