Dr. Anthony Fauci on Sunday pushed back on President Donald Trump's false claims that the U.S. coronavirus death toll is "exaggerated."

"The numbers are real," Fauci, one of the nation’s foremost infectious disease experts, said during an interview on NBC's "Meet the Press." "We have well over 300,000 deaths. We are averaging two to three thousand deaths per day."

He told host Chuck Todd: "All you need to do, Chuck, is to go into the trenches, go into the hospitals, go into the intensive care units and see what is happening. Those are real numbers, real people and real deaths."

Fauci’s interview came in response to Trump tweeting, "The number of cases and deaths of the China Virus is far exaggerated in the United States because of the CDC's ridiculous method of determination compared to other countries, many of whom report, purposely, very inaccurately and low."

Trump responded to Fauci by tweeting: "Something how Dr. Fauci is revered by the LameStream Media as such a great professional, having done, they say, such an incredible job, yet he works for me and the Trump Administration, and I am in no way given any credit for my work. Gee, could this just be more Fake News?"

LONDON — The United Kingdom on Monday became the first country to roll out a newly approved vaccine, made by Oxford University and the drugmaker AstraZeneca, which experts believe could have a big impact globally because it can be kept at regular refrigerator temperature.

Last month the U.K. became the first country to administer the approved BioNTech-Pfizer vaccine. But these vaccines are expensive and difficult to handle because they need to be kept at super-cold temperatures.

The United States has pledged more than $1 billion toward the development of the Oxford-AstraZeneca vaccine, ordering 300 million doses. But a mistake in its clinical trial that raised questions surrounding its exact level of efficacy — but not its safety — has led to delays in approval by the Food and Drug Administration.

Its developers say those questions have now been put to rest, with results clearly showing strong protection against the virus. Brian Pinker, 82, a dialysis patient, received the first of 100 million doses ordered by the British government. "I am so pleased to be getting the Covid vaccine today and really proud that it is one that was invented in Oxford," he said at a hospital in Oxford near to where the vaccine was developed.

However, even the swiftest vaccination program will not dig the U.K. out of its current dire situation. It has one of the fast infection rates on the planet, higher than the U.S., and its publicly funded National Health Service is at risk of being overwhelmed. Its heavily criticized government has not ruled out tightening the already severe restrictions that are imposed across much of the country.