Earlier, Fauci, the director of the National Institute of Allergy and Infectious Diseases, told a U.S. Senate panel that prematurely ending restrictions on commerce and social life could have dire consequences.
"I think we're going in the right direction, but the right direction does not mean we have by any means total control of this outbreak," Fauci said during the 3-1/2-hour hearing.
He urged states to follow health experts' recommendations to wait for clear signs of improvement, such as a significant decline in new infections, before reopening.
"There is a real risk that you will trigger an outbreak that you may not be able to control and, in fact, paradoxically, will set you back, not only leading to some suffering and death that could be avoided, but could even set you back on the road to try to get economic recovery," Fauci said.
The COVID-19 respiratory disease caused by the new virus has already infected more than 1.3 million Americans and killed at least 80,976, according to a Reuters tally.
That toll is projected to climb significantly in coming months.
The latest forecast from the University of Washington's Institute for Health Metrics and Evaluation (IHME) is for more than 147,000 deaths from COVID-19 by early August, up nearly 10,000 from the last projection, as social distancing is increasingly relaxed, researchers said.
Arizona was the latest state to do away with restrictions. Republican Governor Doug Ducey said stay-at-home orders in place since March 31 will be allowed to expire on Friday.
"This is not a green light to speed," Ducey told a news conference in Phoenix. "This is a green light to proceed, and we're going to proceed with caution."
In New York, the epicenter of the U.S. outbreak, Governor Andrew Cuomo said his state needs $61 billion in federal stimulus to help reopen its economy. He called on Congress and U.S. President Donald Trump to support legislation to plug funding gaps.
"This economy has been damaged through no fault of anyone," said Cuomo, a Democrat. "But to get this economy back up again and running, we are going to need an intelligent stimulus bill from Washington."
Trump, who has made the strength of the economy central to his pitch for re-election in November, has encouraged states to forge ahead with reopening businesses that had been deemed non-essential during the pandemic.
