Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, speaks during a teleconference hearing hosted by a Senate panel on the White House's response to the coronavirus, in Washington D.C., the United States, May 12, 2020. (Xinhua/Liu Jie)

If there is not an "adequate" response by the United States in the fall, more infections and deaths are on the horizon, he said.

WASHINGTON, May 12  -- Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said on Tuesday many experts believe more people in the United States have died from COVID-19 than those who have been reported.

"Most of us feel that the number of deaths is likely higher than that number," Fauci told a Senate hearing.

"Given the situation, particularly in New York City, when they were really strapped with a very serious challenge to their health care system, that there may have been people who died at home... who are not counted as it because they never really got to the hospital," he said.

Fauci added he was not sure "exactly what percent higher" the real death toll could be.