Dr. Anthony Fauci, the top public health expert in the US, warned in Tuesday's Senate inquiry that the official death figures for the ongoing pandemic in the country is an undercount, and that the "consequences could be very serious" if the government loosens its safety protocols against the virus.

"My fear is that we are going to start seeing little spikes which will turn into outbreaks," he said.

Fauci appeared before the Senate as US President Donald Trump declared that the nation had "prevailed" in its efforts to boost its testing program, and urged businesses and schools to reopen.

In an email he sent Monday night, Fauci wrote that "if we skip over the checkpoints in the 'Open America Again' guidelines, we run the risk of numerous outbreaks across the US, not only resulting in unnecessary misery and death, but also putting us back on our quest to get back to normal."

Several states have begun reopening their economies despite not meeting the requirements set by the White House, which requires that states must have a "downward trajectory of positive tests" in a two-week period.

In a report by the New York Times, it said that in over half of states loosening their lockdown policies, case figures trended upward, positive test results are up, or both. Around 80,000 deaths from the pandemic have been recorded in the US as of Tuesday, but Fauci also told lawmakers in the hearing that the figures may have been undercounted.

Fauci's remarks to the Senate panel came after the White House announced on the same day that the President will travel to the politically critical state of Pennsylvania on Thursday to bring forth his argument that the economy can be restarted safely and that life can return to normal soon.

The 79-year old Fauci has led the National Institute of Allergy and Infectious Diseases since 1984 and has become a credible public figure. In response to a query from Sen. Bernie Sanders of Vermont, Fauci disclosed that the official death number of about 80,000 in the US was probably low.

In New York City, for instance, Fauci said that there may have been individuals who died at home and who were not counted as Covid-positive because they were never brought to the hospital.

Meanwhile, one risk for Trump is that the coronavirus crisis will become a political burden for him as he guns for another term as president in November. He bets that restarting the economy will strengthen his chances of winning another four years in office, but Democrats have criticized him for what they consider as his administration's poor handling of the ongoing crisis.