Dr. Anthony Fauci, the government’s top infectious disease expert, said Tuesday the U.S. does not yet have the critical testing and tracing procedures needed to begin reopening the nation’s economy, adding a dose of caution to increasingly optimistic projections from the White House.

“We have to have something in place that is efficient and that we can rely on, and we’re not there yet,” Fauci said in an interview with The Associated Press.

Fauci’s comments come as Donald Trump and others in the administration weigh how quickly businesses can reopen and Americans can get back to work weeks after the fast-spreading coronavirus essentially halted the U.S. economy. Trump has floated the possibility of reopening some areas by May 1 and said he could announce recommendations as soon as this week.

When Trump was asked about Fauci’s comments in his Rose Garden press briefing, Trump got testy with Fox News reporter John Roberts, and also managed to take a cheap shot at Fauci.

Trump cut Roberts off to say he didn’t “know what he said,” and added “Nobody knows.”

Here is the transcript of the exchange, from Mediaite’s Tommy Christopher:

Roberts: Mr. President, you talked about having testing and tracing equipment, and the facility for that in place to open up the government. Dr. Fauci said this morning that that critical testing and tracing ability does not currently exist.

Trump: Well, I don’t know — look, I don’t know.

Roberts: Will — will — will it —

Trump: Hey, John, I don’t know what he said.

Roberts: My question is: Will it —

Trump: Nobody knows.

Roberts: My question is: Will it exist by May 1st?

Trump: The individual governors have testing. The individual governors — we have many forms of testing and new testing is being developed.

Our country has to get open, and it will get open, and it’ll get open safely and hopefully quickly — some areas quicker than other areas. But there is tremendous testing and the governors will use whatever testing is necessary. And if they’re not satisfied with their testing, they shouldn’t open. But they’ll use whatever is testing — whatever testing is necessary.

It’s pathetic that Trump had to make a shot like this. Fauci has been nothing but a professional, and only cares about stopping the virus from infecting Americans. Period.

In that same AP interview, Fauci also said that Trump’s briefings were too long, and that his time would be better served just answering a few questions and getting back to work. Fauci also said the briefings were “draining.”

Trump is not happy with a Fox News question about how the current lack of testing capacity in the country is consistent with getting state economies back up and running pic.twitter.com/rVrpv6UaND

— Aaron Rupar (@atrupar) April 14, 2020