The US Food and Drug Administration (FDA) issued emergency use authorization Saturday for Johnson & Johnson's COVID-19 vaccine.

The agency said it determined the Janssen vaccine, third to be approved, met statutory criteria and its known and potential benefits outweigh the known and potential risks.

"The authorization of this vaccine expands the availability of vaccines, the best medical prevention method for COVID-19, to help us in the fight against this pandemic," said Acting FDA Commissioner Janet Woodcock.

The vaccine is administered as a single dose.

"With today's authorization, we are adding another vaccine in our medical toolbox to fight this virus," said Peter Marks, the director of the FDA's Center for Biologics Evaluation and Research.

President Joe Biden called the approval "exciting news for all Americans, and an encouraging development in our efforts to bring an end to the crisis."

"We know that the more people get vaccinated, the faster we will overcome the virus, get back to our friends and loved ones, and get our economy back on track," the US president said in a statement.

The other two vaccines administered in the US -- one from Pfizer-BioNTech and another from Moderna -- require two separate shots spaced weeks apart.

As of late Saturday, nearly 73 million doses have been administered across the country, as states in critical condition like New York pleaded for more vaccines.