Concerns about mail-in voting have deepened after the postal service warned officials in the critical battleground state of Pennsylvania that some ballots may not be delivered in time.

Additionally, it was revealed President Donald Trump had an Oval Office meeting last week with Postmaster General Louis DeJoy amid allegations the billionaire mega-donor to the Republican Party has put policies in place that are holding up delivery of the mail.

The White House told The Washington Post the meeting was a 'congratulatory' meeting because DeJoy was recently appointed to the position but it came before his tense meeting on Capitol Hill last week with Democratic Leaders Speaker Nancy Pelosi and Senate Democratic Leader Chuck Schumer. 

Trump has said he hasn't spoken with DeJoy about the new policies he's put in place in the postal system - including firing executives and limiting overtime work, which DeJoy says is to make the service financially soluble.  

With almost 180 million voters eligible to vote by mail in November's contest, worries have been piling up about whether those ballots will make it to state officials in time to be counted. President Trump has been an outspoken critic of mail-in voting but postal workers charge DeJoy's new policies with causing delays that Democrats say could lead to voter disenfranchisement.