Pharmaceutical giant Pfizer Inc. on Friday became the first U.S. company to apply for emergency use authorization for its experimental coronavirus vaccine, marking a major step in the country's fight against the pandemic.

If authorized by U.S. regulators, the two-dose vaccine, developed with German partner BioNTech SE, could be used in high-risk populations in the United States by the end of December, Pfizer said on its website.

A pedestrian wearing a protective mask walks past Pfizer Inc. headquarters on July 22, 2020 in New York City.(PHOTO NOT FOR SALE)(Getty/Kyodo)

The companies are also moving toward submitting applications in countries including Australia, Britain, Canada and Japan, the U.S. firm said.

They expect to produce globally up to 50 million vaccine doses in 2020 and up to 1.3 billion doses by the end of 2021. They said they will be ready to distribute the vaccine "within hours" after authorization.

The Japanese government has an agreement to receive a supply of 120 million vaccine doses, enough for 60 million people or roughly half its population.

The latest development came just days after Pfizer and BioNTech announced that their late-stage clinical trial showed the vaccine to be 95 percent effective against COVID-19, the disease caused by the novel coronavirus.

No serious safety concerns have been observed to date, they said.

U.S. biotech firm Moderna Inc. is also believed to be on track to apply for emergency use authorization, after saying Monday that its experimental vaccine was 94.5 percent effective in preventing COVID-19.

The nation's top infectious diseases expert Anthony Fauci said at a press conference Thursday that the efficacy figures for the two vaccines are "extraordinary" and offered reassurances that the speed of vaccine development, which has taken years in past cases, did "not compromise at all safety."

The series of successful findings are raising hopes toward a breakthrough in the nearly year-long global fight against the coronavirus pandemic, which has left more than 1.3 million people dead.