The USPS said the figure was up from 100 million ballots delivered as of the prior week
The US Postal Service said on Thursday that it had delivered 122 million blank and completed ballots ahead of next Tuesday's presidential election in which there has been record early voting.
The USPS said the figure was up from 100 million ballots delivered as of the prior week. It added that since October 1, it had been delivering all first-class mail, including ballots, in an average of 2.5 days, while 97.5% of all first-class mail was delivered within five days.
Due to an increase in mail volume, the impact of Covid-19 and efforts to prioritize ballots, first-class mail service performance fell in the week ending October 23, the USPS said.
"We acknowledge that our full focus and prioritization on election ballots is having a near-term impact on the overall on-time performance of other products throughout the network," said Kristin Seaver, the Postal Service's chief delivery officer.
More than 80 million Americans have already cast ballots in the presidential election, according to the US Elections Project at the University of Florida.
That includes more than 51 million ballots cast by mail, a long-standing practice of American elections that is surging in popularity because of the pandemic.
President Donald Trump, who trails Democratic challenger Joe Biden in national opinion polls, has repeatedly said, without providing evidence, that mail voting would lead to widespread fraud. Experts have said such fraud is rare.
Trump's campaign and its Republican allies have filed lawsuits in key battleground states to try to block extensions for counting mail-in ballots that arrive after Election Day.
On Wednesday, Democrats in Congress said recent delays in some mail deliveries could jeopardize timely ballot deliveries.
The USPS is taking measures to insure ballots are delivered promptly, including extra pickups, deliveries and Sunday collections. Through Sunday, carriers will be checking every residential mailbox for outbound mail including ballots.
The Postal Service does not recommend mailing ballots less than seven days before state deadlines. Some states accept ballots if postmarked by Election Day, while others require receipt by then.
US District Judge Emmet Sullivan has ordered the USPS to release daily reports on mail deliveries, participate in daily court conferences and take other steps to ensure timely delivery of ballots.