The Food and Drug Administration has told Johnson & Johnson to throw out about 60 million COVID-19 vaccine doses from a beleaguered plant, people familiar with the situation told The New York Times.

The vaccine doses were made at a factory for Emergent BioSolutions, a biotech firm that's known for producing anthrax vaccines.

The factory has been closed for two months because of regulatory concerns after Emergent BioSolutions discovered that workers had accidentally mixed up ingredients in a batch of Johnson & Johnson vaccine doses.

People familiar with the situation told The New York Times that the 60 million COVID-19 vaccine doses are being thrown away because of possible contamination.

Another 10 million doses will be allowed to be distributed, but with a warning about the factory's manufacturing practices.

Meanwhile Reuters has reported that Europe's drug regulator said on Friday batches of Johnson & Johnson's COVID-19 vaccine made for the region around the time when contamination issues were revealed at the US manufacturing site would, as a precaution, not be used.

The European Medicines Agency (EMA) did not say how many shots were affected, but Reuters has reported it involves millions of doses, making it harder for J&J to meet a target of delivering 55 million to Europe by end of June.

J&J did not immediately respond to Reuters' queries.

The EMA said it was aware a batch of the active substance for J&J's COVID-19 vaccine had been contaminated in April with materials for another vaccine made at the site in Maryland owned by Emergent Biosolutions. 

The production of J&J's vaccine at the site was halted by US authorities and J&J was put in charge of manufacturing at the plant.

The US Food and Drug Administration is close to approving about 10 million doses of the vaccine made at the plant, CNN reported on Friday.

(With input from agencies)