LONDON (AP) — America's top infectious disease expert has apologized for suggesting U.K. authorities rushed their authorization of a COVID-19 vaccine, saying he has "great faith" in the country's regulators.

Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, had sparked controversy with an earlier interview in which he said U.K. regulators hadn't acted "as carefully" as the U.S. Food and Drug Administration.

Fauci said late Thursday that he meant to say U.S. authorities do things differently than their British counterparts, not better, but his comments weren't phrased properly.

"I do have great faith in both the scientific community and the regulatory community at the U.K., and anyone who knows me and my relationship with that over literally decades, you know that's the case," Fauci told the BBC.

Britain on Wednesday became the first Western nation to authorize widespread use of a COVID-19 vaccine when regulators gave emergency approval to a product made by U.S. drugmaker Pfizer and Germany-based BioNTech. Critics have suggested that U.K. regulators emphasized speed over thoroughness when they reviewed data on the safety and effectiveness of the vaccine.

Fauci rejected that idea.

The FDA has to move more slowly because of the high degree of skepticism about vaccines in the U.S., Fauci said. Because of this, U.S. regulators are reviewing all of the raw data from Pfizer and BioNTech "in a way that could not possibly have been done any more quickly," he said.

It will take the FDA at least another week to complete its review, but the U.S. and Britain will ultimately end up in the same place, Fauci said.

"At the end of the day, it's going to be safe, it's going to be effective," he said. "The people in the U.K. are going to receive it, and they're going to do really well, and the people in the United States are going to receive it, and we're going to do pretty well."