WASHINGTON • Dr. Anthony Fauci said Tuesday that he is cautiously optimistic there will be a COVID-19 vaccine by the end of the year or early 2021, but warned that the next few weeks will be critical to tamping down coronavirus hot spots around the country.

Fauci and other top health officials also said they have not been asked to slow down testing for coronavirus, a controversial issue after President Donald Trump said last weekend that he had asked them to do just that because it was uncovering too many infections. Trump said earlier in the day that he wasn’t kidding.

“We will be doing more testing,” Fauci, the government’s top infectious disease expert, told a House committee.

The U.S. has tested more than 27 million people, with about 2.3 million – or 8.4% — testing positive.

The health officials returned to Capitol Hill at a fraught moment in the nation’s pandemic response, with coronavirus cases rising in about half the states and political polarization competing for attention with public health recommendations.

“We’ve been hit badly,” Fauci said. He said he was “really quite concerned” about rising community spread in some states, including Arizona, which Trump was visiting Tuesday to view construction of a border wall and for a rally at a megachurch.

“The next couple of weeks are going to be critical in our ability to address those surges,” he said.

Fauci, who heads the National Institute of Allergy and Infectious Diseases, was testifying along with Centers for Disease Control director Dr. Robert Redfield, Federal Drug Administration chief Dr. Stephen Hahn and the head of the U.S. Public Health Service, Adm. Brett Giroir.

Since Fauci’s last appearance at a high-profile hearing more than a month ago, the U.S. has begun emerging from weeks of stay-at-home orders and business shutdowns.

But it’s being done in an uneven way, with some states far less cautious than others.

Three states with Republican governors bullish on reopening — Arizona, Florida and Texas — are among those seeing worrisome increases in cases.

Last week, Vice President Mike Pence published an opinion article in The Wall Street Journal saying the administration’s efforts have strengthened the nation’s ability to counter the virus and should be “a cause for celebration.”

Then at his weekend rally in Tulsa, Trump called for slowing testing.

White House officials later tried to walk back Trump’s comment, suggesting it wasn’t meant to be taken literally.

Dr. Robert Redfield, director of the Centers for Disease Control and Prevention, left, Director of the National Institute of Allergy and Infectious Diseases Dr. Anthony Fauci, second from left, listen Tuesday during a House Committee on Energy and Commerce on the Trump administration’s response to the pandemic.

the associated press