The White House said on Tuesday that weekly shipments of coronavirus vaccines to the states would rise by one million doses to 14.5 million, as vaccine manufacturers continue to ramp up production. The figure was provided to governors in a call with Jeffrey Zeints, the president’s coronavirus response coordinator, said Jen Psaki, the White House press secretary, on Tuesday. With tens of millions of eligible Americans waiting to get shots, state officials have been clamoring for more vaccine, saying health practitioners could easily double or triple the number of shots they are administering.

Ms. Psaki said the increase was the fifth boost in distribution in five weeks, and said it came just short of doubling the vaccine shipments underway at the time Mr. Biden took office on Jan. 20.

Before snowstorms disrupted vaccine distribution last week, the average number of daily doses administered across the country had been steadily increasing as the two federally approved vaccine manufacturers, Pfizer and Moderna, get more efficient and expand production. While that acceleration was expected well before Mr. Biden assumed office, officials have been anxious to highlight every increase in shipments as evidence that the new administration is fiercely battling the pandemic. As of Tuesday, the seven-day average rate of doses administered across the country was 1.4 million a day, after peaking at about 1.7 million before the storms, according to a New York Times vaccine database.

Many vaccination appointments last week that were postponed by snowstorms and other disruptive weather are resuming this week. In Los Angeles, Mayor Eric Garcetti said vaccinations would start back up again on Tuesday at all of the city-run sites and indicated that people whose inoculations had been delayed by the weather would be given priority over those making new appointments.

At a congressional hearing Tuesday morning, top officials from Pfizer and Moderna reiterated previous supply commitments in front of lawmakers Both firms promised earlier this month to deliver a total of 400 million doses by the end of May, weeks ahead of schedule, and a total of 600 million by the end of July.

John Young, Pfizer’s chief business officer, testified that his firm will be able to ship more than 13 million doses per week by mid-March, compared to a weekly shipment of just four to five million at the start of this month. He cited a variety of reasons, including federal regulatory approval to count each vial as holding six doses instead of five, more efficient production processes and faster laboratory tests of the vaccine before it is shipped. Dr. Stephen Hoge, president of Moderna, testified that his company expects to double its current shipments to more than 10 million per week by April.

More supply is expected to come from Johnson & Johnson, but not as quickly as federal officials initially had hoped. Federal regulators are widely expected to grant emergency use authorization for that vaccine by early next week.