Cases of the coronavirus continue to wreak havoc across the United States.

States like California, Florida and Texas have now surpassed New York in the total number of cases since the pandemic began.

President Donald Trump took to Twitter about the surge in cases. He said in part: "...we do much more testing than any other country in the World. If we had no testing, or bad testing, we would show very few cases."

Meanwhile, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, testified before a House subcommittee on Friday.

"The increase in cases was due to a number of factors, one of which was that, in the attempt to reopen, that in some situations, states did not abide strictly by the guidelines that the task force and the White House had put out," Fauci said.

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Other health officials also spoke on Capitol Hill about the federal response to the pandemic.

"We can get back without these unintended consequences. The face masks, the social distancing, the hand hygiene, staying smart about gatherings," said director of the Centers for Disease Control and Prevention Dr. Robert Redfield.

Health officials said a continued backlog in test results have been an issue, but reiterated that there is improvement.

"This is not only about numbers, it is about getting the right test, at the right time, to the right person," said Admiral Brett Giroir, M.D., Assistant Secretary for the Department of Health and Human Services.

While test results have been tough to come by for some Americans, Fauci still believes there is hope that a vaccine will come soon.

"We feel cautiously optimistic that we will have a vaccine by the end of this year, as we go into 2021," Fauci said.